Guildford central can be ludicrously overpriced compared to prices round and about.
It really does have very good train connections, and I would look at these carefully.
In the villages without a train station you get a lot more for your money (with some exceptions, such as Cranleigh), but then transport will be pretty shit for teenagers with no car.
The line south of Guildford towards Portsmouth gets leafier, and you've still got the direct link to Waterloo.
Godalming is a posher, smaller version of Guildford, and only two stops from Guildford mainline, 15 minutes to London Road. (Farncombe is essentially north Godalming, but the shops are near Godalming station).
South from Godalming you've then got Milford and Witley, which are super-posh villages with nothing going on and fewer trains that Godalming.
The next stop is then Haslemere, which is a bit smaller than Godalming, but with a good train service.
North from Guildford is Woking, which is fugly but very convenient for trains to London, and has a good number of shops and the like. Worplesdon station, in between, is in the middle of nowhere essentially.
On the Reading - Gatwick line you could consider Dorking or possibly Wokingham.