What problem do you two have that stops you from squatting? Is it an injury you had diagnosed? Or is it just unidentified pain?
There really is no "good alternative" or substitute for squats/deadlifts. They are your two most important lifts. Leg press might work some of the same muscles, but it doesn't come close to a squat in terms of building real strength.
Like I said, you really need to try to find out what is causing the problem, and fix it. If you take the easy way out, and just start doing leg presses, you will not see close to the same results.
There really is no "good alternative" or substitute for squats/deadlifts. They are your two most important lifts. Leg press might work some of the same muscles, but it doesn't come close to a squat in terms of building real strength.
Like I said, you really need to try to find out what is causing the problem, and fix it. If you take the easy way out, and just start doing leg presses, you will not see close to the same results.