I am an old GOAT (Graduate of the Oxfrod Air Training School) and live in the area so when you decide where you want to stay, I might be able to give you some idea of the pros and cons.
I assume you will drive in to the airport - will you be working like a maniac or will you be chilling in the city in the evenings?
Can't the school provide cheap rooms?
Country - about 15 mins
http://www.s-h-systems.co.uk/a12130.html