Hiking, Scrambling, Mountaineering, and Climbing

Yeah, avoid Snowdon! I did a walk last year that went up to Glyder Fach from Pen-y-Gwryd then took in Glyder Fach, Y Garn, Foel Goch and Elidir Fawr and back down to Nant Peris. Glyder Fach is totally worth the climb - it has some incredible rock formations at the summit. You get great views of Tryfan and Llyn Idwal, and there's an entertaining descent from Glyder Fawr down to Llyn-y-Cwn which is challenging without going over the line. The range is on the opposite side of the A4086 to Snowdon, so it has some pretty handy public transport options / parking spots you can make use of (you could park in Nant Peris, for instance, and then get a bus to the start of your walk). There's also a decent pub in Nant Peris which makes a great end of the walk destination. I've got a gpx file somewhere if that would be of interest, although I'd probably do it differently and maybe cut out going up Elidir Fawr in favour of taking some time to explore the Devil's Kitchen.

Give Moel Siabod a try, can start and finish at the cafe, much quieter than Snowdon. There's a nice easy walk around Cwm Idwal, or hit up Pen-yr-Ole-Wen if you're keen for a mountain around there. For a longer jaunt, have a look at the Oggie 8, takes 12 hours to do but you can do the first half (north side of the Ogwen) on it's own which is considerably shorter. Aber Falls is also worth a day out, and the walks around Sychnant Pass too.

For the less keen, head to Llandudno for the Orme and a couple of great taprooms, or Conwy for lots of nice pubs/cafes/great castle/seaside scenery.

@Eejit's suggestions are great too. Let me know if you have a particular place in mind, I used to live around there.

Can't offer any Wales tips but I'm up to Ambleside in couple of weeks, will give Red Screes a go!