@sozobe,
I used the stepper yesterday, it was this weird thing where you lean back and kick your feet. Not quite a dying cockroach but I did feel like that after 5 minutes. Oof. Harder than the elliptical.
I find treadmill easiest, I do 30 mins and I'm fine but I am mainly striding and not running (only a minute or 2; it's all I can handle so far). Bike seems second-easiest (20 minutes usually), again I'm probably not pedaling as hard as others do. Then rower (15 minutes or so); I just find it boring but I do it (the flywheel is a bit of a fan and the gym is hot, so that's a bonus). Then elliptical (10 minutes if I'm lucky). Then the dreaded stepper machine from hell.
As for weights I was doing 70 for the first set, then kept going down, 50 I think for second, then 40 or so (I didn't really watch but that's about where they ended up). I've been doing maporsche's idea, modified. Get in, lift free weights about 25 times, then treadmill, then 9 reps on 3 machines, then rower, then 8 reps on 3 machines, then elliptical, another 8 reps on 3 machines, then bike, then 25 situps. That all takes me about 90 minutes. I'd like to work up to 120 minutes on Fridays. Mondays will have to stay at 90 minutes as I need the recovery time plus I hit rush hour if I stay any later. Hence I'll work on more speed and/or heavier weights when I make it to my endurance numbers. Mondays are upper body, Fridays are lower body. If I go in any other day (which I will later this month as I'm going to have some Mondays off), I'll do more lower body which includes core.
That's the plan.
I just realized I have a more coherent plan for fitness than I do for my career.