Have you considered talking to a PT about it? Seriously, it's their job to help people work with disabilities and define what's a good level of fitness given a specific condition and to find appropriate goals. (IIRC, it's your feet, right?)

FWIW, if I don't work out, I can lose many of the above abilities easily. I'm keenly aware I'm temporarily able-bodied. (So is anyone who lives long enough, but you get my point)