Can you drop into a harder gear and simulate a hill that way? Intervals are also good for increasing aerobic capacity. I'm not keen about the gym & leg presses because the type of muscle used in weight lifting is different than the type used in cycling (type II vs type I) and it does nothing for your aerobic capacity.

Don't get me wrong - I love to lift weights. But research has shown that sport specific exercise is the best way to get in shape for a specific sport. (Duh...they pay people to do this research? Where can I sign up? _