The amount of calories you burn while lifting weights depends largely on your body and the way you lift weights. I burn a similar amount of calories (if not more than cardio) while lifting if I'm doing it properly - intense effort, 12-15 reps, very little time between sets. I usually switch from machine/exercise quickly, doing 3 sets of each exercise before moving on to a different muscle group.

For example: Leg press, 12-15 reps - directly to hamstring curl, 12-15 reps - back to leg press, etc. to 3 sets of each

If I am not able to do back-to-back sets of complementary muscle groups (chest/back, quads/hamstrings, abs/lower back, biceps/triceps, etc.), I do tricep dips or wall-sits between sets so I'm keeping my heart rate up. My heart rate gets into a cardio zone while lifting if I'm doing it properly.

Personally.. I'd ride the bike on days when it's feasible, and drive when it's not. Take fun classes if you can - I find that spinning for me has been a lot more productive than me running/doing cardio on my own. Mostly because I have someone telling me what to do and I just obey without thinking about it.