Ranmore stuff is also harder to find, plus carrying on to Box Hill is pretty much just NDW/bridleway sort of stuff.
If you can’t tag along with anyone then make your way to Pitch/Holmbury/Peaslake (in that order) as mentioned above. If you don’t know you’re way around then I’d recommend heading either XC to Albury Heath and then up to the top of Pitch, or just go A25 into Shere and up from there.
Naturally depends how much time you have. NDW is (I think) off limits to bikes, but a fair few still use it. Nice views, but nothing much to do unless you know your way off piste.
Mainly bridleways around St Marthas etc, so you kind of need to head into Winterfold at least before you start seeing the proper stuff.
Others in the area might know other stuff though.