I would also sugest hiring a car, definitely the best way to get around as a 2 hour journey by car can turn into a 5 hour one by coach. If you want to do it on the cheap and have total flexability, invest in a tent. Between camping and couch surfing you will save loads of money.And make sure if you hire a car it has a sat-nav. our roads are probably some of the most confusing in the world.
Try not to just stick to the cities, get to the peak district and the lake district...our best national parks. And if you want to meet real characters, find a small village and spend some time in the local pub, it can be hilarious, there are some 'interesting' people in the uk