Most recommendations would be to seek out Nirvana (Westcott) or Pedal n Spoke (Peaslake) > chat to folk in there and pick up a couple of maps. Even so, you’ll probably struggle to get a lot in because you’ll likely miss a bunch of turns etc and therefore overshoot some of the trails.
You might find someone here to hook up with. I’m aiming to get out that way mid-Wed pm but need to clear a load of work first.
If you don’t have a car then Dorking or Gomshall are your best staring points.
Do a search on here (and Google) to find various trail stuff. There are a fair few other sites dedicated to the area so you should be able to at least have some idea beforehand.