I am basically in exactly the same position as you. I live in a Hamlet (doesn't even have a post office) which is a 45 minute walk from the main bus route. From there, I have to travel and hour into my local Hull. Other than that, there's a rather bad town about 8 miles away, but that's got virtually nothing in it anyway. My parents also refuse to drive me anywhere.
If I were you - and I understand you don't want to get a taxi? With enough people they can be pretty cheap - you could either a) all grab a tent and find somewhere to sleep in town (sounds kinda grotty but it could work for fun fun times and bonding session - or get a taxi. It'd probably work out as less than ten pounds each or something, and that'd be worth it if you spent the whole day in town - shopping, cinema, meal, club, bar... etc.
Anyway, good luck x