Just do what you can and build up. Run at a slower pace so you can run longer.

Bike - you can go forever on a bike.
EFX elliptical - you can go forever on these too
Stairmaster - good leg workout, wouldn't recommend the day after legs cause I'm sure you'll be hurtin.

I just do enough cardio to get my heart rate up and hold it for a while so I can work myself back into shape. An hour on the treadmill is a lot - I'm not training for a marathon.

When you hit your clen, throw on a long sleeve shirt and run indoors on that. It'll help you sweat a lot if you're looking to cut up.