Circuit training is great cross training. You can improve strength and stamina and there are a ton of ways you can progress. It is also really convenient, time and space effective and caters to a lot of different levels of fitness.
Pick out 6-10 exercises and do 2-4 circuits depending on how much time you have and how hard you want to work. You can spend 30 seconds to one minute on each station for a guide. I like minimal rest and hammer through a 20 or 30-minute session but factor rests in if you need them.
Here are three varying circuit suggestions. But you can alter them to suit yourself and your abilities:
1**Squats, skipping, push-ups, shuttle runs, lunges, shuffles, pull-ups, core, shuttle runs.
2**Squats, shuttles, push-ups, step-ups, pull-ups, skipping, core, shuttles.
3**Squat jumps, push-ups, step-ups with a knee lift, pull-ups, burpees, core, sprints, core.
I wouldn’t try the last option unless you have good technique and a decent level of fitness. And make sure, as always, you have a warm-up and cool-down.