The Reverse Quarter To; 2 Market Towns Joined by a Bit of Rough, a leisurely 4 hour (plus lunch) downhill ride.

This ride grew out of a conversation with @skydancer & @moorhen when they took up my suggestion from a Wests Beers to visit the Ruislip Great Barn/Duck Pond Market a couple of Sundays ago.
The date is Saturday 27th October. The aim is to be off the towpath before the light fades.

We assemble in Watford,
easily accessible by bike,
by Underground, Metropolitan Line, or join the ride in at Northwood Hills,
London Overground from Euston to Watford Junction,
Willesden Junction to Watford High Street
link to TfL 'Bikes on Trains' page;
https://tfl.gov.uk/modes/cycling/cycling-in-london/bikes-on-public-transport#on-this-page-3)
We will cycle up the not quite vehicle-free High Street.
Clearly Watford Town Councl have heard we are coming and are busy relaying the paved surface of the High Street, where it serves as a longitudinal Bus Stop.
We will eschew the chain coffee shops of the ravenous InTu shopping centre, (which having engulfed the tired, old Market Shopping centre, may be funding the revamp of the High Street), for the independent GoKula on Market Street. (They claim to use organic coffee beans, but had no label or pack I could photograph).

We will be 46 years late to enjoy a pint of locally brewed Benskins Bitter,
https://en.wikipedia.org/wiki/Benskins_Brewery

When everyone has sated their caffeine requirement, we pootle off past the football stadium along Vicarage Road, and setting a theme for this ride, proceed over a hump-backed bridge over a dead railway line. Continuing through an unlikely estate, we curve round a playing field and find ourselves on the Ebury Way,
https://en.wikipedia.org/wiki/Ebury_Way
part of the route of the never completed Watford to Uxbridge railway line
https://en.wikipedia.org/wiki/Watford_and_Rickmansworth_Railway
(converted by 3 Rivers council into a soft gravel ride), crossing three rivers,
the Gade, the Chess and the River Colne, and the Grand Union canal,
down to Batchworth Lock,
http://www.rwt.org.uk/around-batchworth
the former boat-building heart of Rickmansworth.
(Visitor Centre, toilet & refreshment stop?)

Crossing the dual carriageway we find ourselves at a large Tesco, built on the site of Frogmoor Wharf, (recommended for provisions for Tramps' picnic later), and then the access road to The Aquadrome Local Nature Reserve
https://www.threerivers.gov.uk/egcl-page/rickmansworth-aquadrome
(Public toilets available).
The Cafe in the Park, https://thecafeinthepark.com/
is good but pricy, (and they don't allow picnics on their benches).

The Aquadrome has good all-weather paths around the lakes/old flooded gravel pits, so we could traverse them to see the Autumnal aquatic birdlife.
Stockers Lake, the Herts & Middlesex Wildlife Trust site,
https://www.hertswildlifetrust.org.uk/nature-reserves/stockers-lake
is home to London's largest heronry, (typically 50 breeding pairs), but the edge footpaths are not really bike-friendly. Keener bird watchers should bring their binoculars.

Then, we get onto the towpath of the Grand Union canal.
I have read with dis-belief people posting about commuting along the canal towpath, then I joined the recent Felafel Ride and rode the paved towpath between Edgware Road & Ladbroke Grove. Admittedly some of the paving slabs rocked as you cycled over them, but the surface was smooth & true.
The towpath here is rough gravel tending to rubble and hard core, (broken bricks not a musical accompaniment), as it seems the Canal & River Trust have done nothing to repair the damage done when some shysters trenched along the tow path 15-odd years ago to run a fibre cable between London & Birmingham.
mespilus jr. can confirm it can be cycled on a road bike fitted with 25mm Lugano's, but Marathons might be a better bet. Some recent pothole 'renovation' has incredibly used large, rounded aggregate that merely parts like the Red Sea under your tyre, giving no grip and rendering steering a lottery.

Proceeding south along the towpath, we go past Maple Cross water treatment works, and sun dependent, maybe stop in the Coy Carp for a refreshing beverage, (* if there are queues as per Sunday, we have another option), with views of both the canal and the majestic River Colne, (the traditional western boundary between the good people of Middlesex and the yokels of Buckinghamshire).
We may well see Red Kites wheeling in the skies above, as we sit in the lee of one of the last few Chalk Downlands in London. Harefield, up the hill, is sited on the last outcrop of the Chilterns, and we pass the wreckage of the last chalk quarries on the canal. The railways allowed the cement industry to source its chalk, cheaper from elsewhere.
Passing under Moorhall Road, we have the option* of 'The Bear on the Barge' if The Coy Carp again had too few barstaff. Eyes up, I saw a peregrine falcon fly over here, on Sunday.

We cycle under the Chiltern Line, passing through glorious brick arches, then down to a concealed bridge, Denham Deep Lock and Fran's Tea Garden, (which looked decidedly 'Shut' on Sunday), with views from the tea garden of the above-mentioned bridge, and if we are lucky foot long trout in the river. The Colne Valley visitor centre is just yonder, along a shared all-weather footpath,with public toilets. The benches make this the venue for our Tramps' picnic. Outside the overgrown logcabin (that also house the offices of Thames Valley Groundwork Trust), just beyond the covered seating, we will find the pretty River Misbourne, that runs down the valley of the A413, from Denham to Amersham & beyond.
(Heathrow T5 was built with gravel excavated from the Colne Valley.
The necessary pre-extraction geological survey revealed a Roman well. A lifesize recreation well is near the Visitor Centre).
We should be able to find the weir where the Colne bifurcates, allowing the man-made River Frays to steal some its flow.
https://www.hillingdon.gov.uk/article/8989/Frays-River
Past Roger's boatyard with the floating drydock, in the distance we can see the Big City glass tower blocks of Uxbridge, but first we go under the A40, then into the maze of Canal, River Colne, man-made River Frays, and their many intersections, down to the edge of Uxbridge.
The Swan & Bottle steakhouse now faces the Parexel office block, which some say resembles an ocean-going liner.
Under the Oxford Road we encounter the Crown & Treaty pub, a 16thC brick-built wonder that Uxbridge does its best to ignore
https://en.wikipedia.org/wiki/Crown_and_Treaty
The revelopment will not be complete by the time we cycle past.
Past the Coca Cola UK offices, down past the last timber importers yard in Uxbridge, now being redevelopped as canal-view housing, and little bit further south where large Carp live in the canal, which will approach the bank for bread.
Then, back into central Uxbridge for two dull shopping centres/chain cafes and the impressive terminus of the Metropolitan & Piccadilly lines back to the Smoke.

For those vexed & fatigued by the day, Uxbridge does offer a Quaker Meeting House, where a few quiet moments of contemplation my prepare one for the journey home.

I seldom eat in Uxbridge,
but can reccommend Cai Xin, a true 'hole-in-the-Wall' place for filling noodles,
(mespilus jr. and I had Tramps noodles, on a seat in the pedstrianised zone, before the showing of Blade Runner 2049 last year),
and the Uxbridge Mangal does a full range of meals beyond its frontline kebabs.

For those better served by the Central Line, I will be cycling back towards West Ruislip station. Some of the approx. 3 miles will be on shared paths through Swakeleys Park, a legacy of a previous Mayor of London.

Logistics.
London Overground.
I checked at Watford High Street station, (photo in 1st photo album), the timetable states Saturday trains from Euston are hourly.
The 09.17 from Euston, passes through
Willesden Junction at 09.31
Harrow & Wealdstone at 09.46,
arriving at Watford High Street 10.00, which is bang on for this outing.

LNWR/West Midlands trains
https://tinyurl.com/y9vc7lml
Euston 09.24 arrives at Watford Junction 09.39
or
Euston 09.34, Harrow & Wealdstone 09.46, Bushey 09.52*, Watford Junction 09.54
(*About 4 minutes by bike from Watford High Street station).

Timings.
This will be a relaxed ride.
I've made two recce trips.
The 3-odd miles of the gravelled Ebury Way took about 20 minutes,
stopping for lots of pictures. I would suggest we blat down it, then cycle back up,
and stop on the 2nd pass for photos.
From the coffee shop to the Aquadrome is only about 4.25 miles,
so we could easily loop a lake or two before proceeding, after stocking up at the Tesco.

From The Aquadrome to just about the finish,
(proving 'No Good Deed Goes Unpunished', I p*nct*red venturing onto an industrial estate,
where a building I worked in, is no more and the site is now a Premier Inn/Beefeater),
is 9 miles and again many stops for photos, but not for the 'Tramps Picnic', took 90 minutes.

With adequate weather we will have plenty of time and be on the way home before dark.
If it is sunny bring your sunglasses, we will be cycling into 'horizontal' Sun.

Currently some combination of this laptops W10/Firefox is stopping me uploading photos,
but,
if like the girl in the Billy Bragg song you want to 'open the bottle of pop too early in the journey', I will attempt to upload them to a Google Drive folder and place links here later.

Photo Albums

https://drive.google.com/open?id=1s35k04l1KgaM-M6PdaYDGmFlAcpTwQvn

https://drive.google.com/open?id=1yYBfV8LLUwP1s67CNMOX3mFFwf8LWveA

Duty of care
Watford High Street should be newly re-paved for us. The roads to the beginning of the Ebury Way are fine, but with potholes.
The Ebury Way is fine self-compacting angular, crushed gravel. Hard braking will lead to (controllable) skidding.
The Aquadrome is tarmac based pedestrian footpaths.
This is not your Regent's Canal tow path.
The best of it is oversized gravel. Parts are rutted mud, other obscured by large fleshy, heart-shaped poplar leaves, rather than the laceolate willow leaves, there are some isolated areas of no-grip rounded aggregate, but none of it tyre-damaging. The tow path is surprisingly narrow under some of the original bridges, and some of the inclines down past the locks are unforgiving.
If today, (a Sunday), is typical, we will encouter many pedestrians, with dogs, fishermen, and there are many 14-day moorings, with geezers carrying out essential repairs on narrowboats of dubious weatherproofness, but as we are not attempting PBs we will saunter past these mobile chicanes and have a great day out.