Maybe a helicopter tour would be the best way to see the Great Wall and possibly other remote landmarks, and would be much easier given your husband's mobility issues.

While I understand you do not like moving between hotels, I would highly recommend that you consider staying at ASP for at least a few nights. The hotels could even do the packing and unpacking for you. While moving between hotels is a hassle, remember that it might actually save you a lot of back and forth trips when you go sightseeing.