Mountainbiking is probably my favourite, I cycle around 45/50 min 3 to 4 times a week. Our terrain here is real steep , so I get a real good workout in that time too! I felt it benefitted me a lot more than road cycling , which was time consuming and felt like it needed to be longer to benefit. I use my MTB a lot on the roads too, the drag of the tyres makes it a better workout still. Try not to go too crazy on Weight Lifting , I have lifted since age 16 to current (28). I had to stop all together for a couple of years, It was making my arm pump issues real bad. I have now worked out a way so I am not over tensing my forearms etc when I lift. Pounding motos and my extreme enduro loops in the woods keep me real fit and strong! They are real steep and intense and some pushing, shoving and lifting involved. Do not over do training either . Like Rod said, your body need the rest and sleep!