Garw valley for me is the best, yes its only 3 miles in total but what you get from it is amazing. Steep climb up and fun packed down.
Dont bother with Skyline if you dont know the route, tree felling has cut the official route down loads and the diversions are shocking to the point it actually misses the still open stuff, but the July descent is still awesome. The whole original skyline loop is still perfectly rideable if you know the area or have GPS maps.
If i was travelling down i’d be doing W2 wih extra stuff on the wall at the bike park. Or if you want some fun, park at the bike park, ride the fireroad up to end of Picadilly and do new 373 and graveyard loop, carry on down ziz zags and take the Enduro shortcut back up then mess about in the bike park and do the extra loop just past the zig zags.
Or you could go do the masts. 😉
All perfectly doable on a hardtail (maybe not the masts), ive ridden them all loads of times on mine.