Somebody asked this to Jim on his website the other day (in regards to squatting) and this was his response:
Answer: You are welcome to use the Smith Machine but I wouldn't. I'd just do lunges, one leg squats, deads, etc. I'd rather leg press than use the Smith Machine.
Make the best out of what you have, but don't expect the same results if you can't get the right equipment. Why not just get a gym membership for yourself and leave the wife and kids out of it?