I'm brand new here aswell, but earlier this year I lost 25lb before doing any weights work. That took me from 275 to 250 at 5'11
I did fasted incline treadmill walks as part of my programme, and that seemed to work well.
After I got a bit fitter I also started doing a bit of kettlebell work as a higher intensity cardio.
The circuit I did was:
1 minute two handed swings
30 seconds each hand, squat, clean and press
30 seconds each hand, one handed swings
30 seconds each hand, snatch
1 minute alternating hand swings
90 second rest, and repeat.
I would do this for about 20 minute (Three circuits). It really got the heart rate going.
I know your shoulder wont let you do something exactly like this, but could you do sets of swings with 1 hand??
The other thing I did with the treadmill was walking intervals. I always kept the speed the same, but would go from flat to incline. I timed the intervals by songs on my I-pod. 1 song flat, 1 song incline. Seemed to keep it more interesting for me, and that was the main thing for me. Keep it interesting.
I also went for walks during my lunch break. My motto was: 'keep fatty moving', and walking is easy enough that you dont ever really burn out on it. I tried to move around in some way for about an hour a day.
Can you swim with a kickboard and fins, or something like that??
The biggest thing though is to eat right. I can't do the whole ultra low carb thing, so I just ate 3 healthy meals a day, but no carbs (I define this as bread, pasta, rice, potatoes) after lunch.
I don't know about eating while healing, so can't help there.
Good luck, and keep us updated.