I am new to the sport and would appreciate any advice from the veterans out there.I have an opportunity to purchase a Trek 4500 that has been ridden three times. Most of my riding will be wood's trails on flat ground, but do intend to head for the hills and do some riding. As I know nothing about mountain bikes and do not wish to purchase something that I will later regret buying, I would appreciate advice on this bike or any other bike that would be good for a new and weekend rider.