Cardio is def the most important pre-surgery. When I first started after surgery I started with a personal trainer through a physical therapy place. They worked with me to make sure the exercises I was doing were SAFE for me to do. It's obviously not a cheap route but I did it for 3 months to get me going and then I went off on my own.
Well, at my current weight everything is cardio. Doesn't take much to get the heart pumping...