Whytes + the Wall (w2) takes in a lot of the good stuff. Start from the Dropoff. Or Whytes, bit of lunch, Penhydd from the other centre. We did a great loop starting on whytes, first descent off windy point, over to the Wall, Wall descent, cut to other centre,Penhydd and then back on the railway. Easily doable in a day but you need to watch for the signs.
Prefer those trails on the HT. The July trail is fun on a FS, found skyline a bit dull as it has ALOT of fireroad.
Tyres, whatever you have It's rock hard there, just let them down a bit and have a mud free day.