There's tons of riding out of Guildford itself.
From Guildford you can head east along the ND way towards Dorking, which gives you access to the Surrey Hills around Peaslake, Leith Hill, Holmbury Hill, etc. where GlenP's outfit is based.
Or west along the NDW towards Farnham which gives you access to Ash, Puttenham Common, Godalming and from there the Devil's Punchbowl at Hindhead.
Or 25 miles South down the downslink and then you've got access to the SDW which is classic downland riding.
Or to the NW there is a huge tract of mainly open access military land which is criss-crossed by singletrack and is the home of the Gorrick and ACU events (Tunnel Hill, Porridge Pot, Minley, etc.) Which eventually leads onto Swinley with the Gorrick / BOB maintained singletrack.
So, a few big hills around the ND / Surrey Hill / SDW area, the rest isn't big by Peaks/Wales standards but is very undulating and as anyone that's done the Gorrick Enduro will tell you lots of ups and downs still makes for plenty climbing in a ride.
Post up again when you're down here and there's a few folks down here would be glad to show you some of it.