I'm 66 and have Spinal Stenosis. I can't walk real far without leg numbness, but thank goodness, I can currently ride my bikes as far as I want.
I ride in position 3 on my road bike which I try to ride more often for fitness.
I recently converted my old Trek 970 to a beach cruiser and use it when riding the beach trails with my significant other. I'm in position 5 on it.