Supersets with alternating bodyparts are a great way to condense one's workout, keep the heart rate up, and just keep yourself from sitting at the gym not doing anything. It's probably not optimal for building maximal muscle/strength, but at this point I'm just trying to keep what I have and make sure I don't end up injured. I get a good workout, end up panting & dripping sweat, and I'm in and out in 30 minutes or less.
For heavier/bigger exercises, I'll alternate them with some kind of ab or calf exercise. Otherwise I'll just pair two different exercises together and go back and forth for a couple sets
Bench press/crunches
Rows/calf raises
DB pullovers/BB curls
Flies/DB rows
etc.
It works well for me.