Being a person of size myself, I'd suggest swimming and walking for your cardio sessions to preserve your knees.
One of the most successful programs for me that I found on this site was thus:
pick a leg exercise, an upper body pressing exercise, and an upper body pulling exercise
Then do them 5x5, heavy load, long rest
then do them 4x8, medium load, medium rest
then do them 3x10, light load, short rest
Then you get your strength sets and your hypertrophy sets in the same day, but it does take a couple of hours.