This is a quick one, but will leave you sore, I can assure you that!
Warm up 10 min on the stair master
3×15 narrow leg press
3×12 wide leg press
3×12 (each leg) curtsy lunges
Cool down 5-10 min on the stair master
If you are trying to make your squats a circuit- get rid of the bar and add dumbbells. Between squats, add in a bicep curl or shoulder press.
Good luck walking tomorrow 😉