My grandfather was never a biker but did walk a lot. a spill broke his knee and then some other health issues kept him not walking far anymore. i know it bothered him a lot. He and my grandmother are part of the reason why i ride as much as i do. and your age just makes me do it as well. i turn 55 next week.
maybe consider a stationary bike or dumb trainer, hard to fall off from those and no traffic, stopping, or turning. but, no scenery either but a small price to pay to continue to ride. stay away from rollers though, you *can* fall off those.