In reply to JimR:
I bought an iwalk2 ( see my pics ) to use instead of crutches with my non weight bearing ankle ( below knee cast ).
If you stick with crutches look up tips for domestic chores on crutches.
I found crawling round the house most efficient.
Made a low seat ( out of Kingspan insulation ) so I could shower with leg outside.
Tips I found later were to make a brew in a flask then carry in a kangaroo pouch/bib to your chair.
When you get a weight bearing cast, I found a plastic boot shell fitted really well over it, so well I spend a lot of time at Kendal Wall.
If you are looking at cardio the turbo trainer sounds a good idea.