Thanks everyone,
Ive heard mixed reviews on extensions - my PT said to stay away from them (too much stress on the knee) but I have also heard that if you limit the ROM to the last 20 deg that they really isolate the VMO. So, I just might try incorporating the 4 exercises that y'all mentioned into my leg day for the Fall. How does this sound:
Front squats: 2x8
Split Squats: 2x8
or Step ups: 2x8
Unilateral extensions: 2x8
plus
SLDs: 2x8
Hamstring curls: 2x8