Basically on the edge of the Surrey Hills vastness of trails there.
Big crazy loop: Newlands Corner -> North Downs Way all the way along to Ranmore -> Dorking -> as far as Box Hill and surrounds if you like and/or south to Leith, west to Holmbury -> Pitch -> Winterfold, north to Farley Heath -> Blackheath, and up St Martha’s and/or Chantries.
Or vice versa and variations of. And then along the way of all of that are loads of trails. Majority of the singletrack stuff though is around Holmbury/Pitch/Winterfold.
A struggle to cram it into half a day, more so if you mess about on all the fun singletrack you find on the way 😀
Shorter is North Downs Way and drop to Gomshall and make your way towards Peaslake, then up a hill there and whatever, then back via Winterfold & Blackheath etc.
Or quick is NDW loop around Albury to Blackheath and back via St Martha’s and Chantries. Mostly an XC spin that as not much in trails, though nice scenery.
No waymarking. XC wise the only signs are North Downs Way and Downs Link really. Singletrack the only one signed is Summer Lightning over on Leith. Nothing else is (and only two other trails are official-ish).