I haven't hit the weights in far too long... but I will say that for what your goals are, you should definitely integrate squats into your workouts. Being that it's an exercise that engages so many large muscle groups, it tends to drive your testosterone levels up faster than other exercises.
If you want to put on some mass, you need elevated testosterone levels. Taking a natural testosterone booster isn't a bad idea either.
My back and knees are so f***ed up these days, I can't squat enough to make it worth while.
