You can definitely ride offroad on the old style mountain bikes. I used to ride a department store bike ($200 job) on the tracks in a national park and had a bl

You can definitely ride offroad on the old style mountain bikes. I used to ride a department store bike ($200 job) on the tracks in a national park and had a blast, and it teaches you good riding habits as well. On a full suspension bike you can make all kinds of mistakes and they will be covered but on a rigid or hardtail you pay for those mistakes more dearly. I ride a full suspension trail bike these days. It's really comfortable and I can go on much longer rides and hit all kinds of gnarly terrain. But I still like to get scrappy on my old hardtail sometimes :)