We're in the middle of the same thing.
Spent months trawling the whole of Bucks & Herts. Decided we loved the Harpenden area etc, but weren't impressed with what we could get for our budget (pretty close to yours).
It's a lovely area, but train prices to London are horrendous and it's not that handy if you want Waterloo.
St Albans was also a pain in terms of houses being near the station were small and v v expensive, but getting to the station in the morning by car was pretty dire.
We did a sudden switch to Surrey/Kent border - season ticket is nearly half the price, massively more in terms of house for money and found a house that ticked all our boxes in terms of location, commute, secondary schools and amenities.
The website we loved was www.commutefrom.com. You can set the station you need to get to and the max time you want to commute. We then looked at all the places near relevant stations and went and visited those that sounded like possibles.
For Waterloo, Berkshire is a good place to look - you are also in the catchment for some of the Bucks grammar schools in some parts.
I grew up in a tiny village and thank god, my parents sent me to boarding school or I would have gone mad. Holidays, we just joined the Young Farmers and got sloshed at parties and snogged the local yoof in barns. Holiday jobs (bar picking strawberries) were non existent and my parents acted as a endless taxi service. Hence, we've picked a big village with a 5 minute, very safe walk to a mainline station with a quick and reasonably cheap commute into London and the nearest big towns.