-
Cool, cheers. So something long cage like http://www.chainreactioncycles.com/shimano-deore-m610-10-speed-rear-mech/rp-prod108792 with compact rings?
Just going to go friction shifting on the downtube yeah so there shouldn't be any compatibility issues right?
The cheaper I can make it the longer I stay away for
-
No, the 10 speed Shimano MTB derailleur won't work with the 10 speed road shifter.
Get the 9 speed MTB one, that'll work with the 8/9/10 speed road shifter.
11-34 with 50/34 give you a very good range with a very low gear of 26GI for the worst.
Having said that, all modern Shimano long cage road derailleur work well with a 11-32t cassette (28GI).
If you're carrying a lots then 28c would be a little too small.
Single rack with a pair of panniers, even 23c would be fine.
Triple is not a necessity, compact (50/34 or 46/34) is plentiful with a wide range cassette on the back (11-28 or 11-32), 8 speed is much cheaper, very strong and last for ages.
You can run an mtb derailleur and cheap friction shifter on the downtube to keep cost down with the additional benefit of being cheap and easy to look after/replace.