I'm only 67 (and a half) so my approach might not work for OP. But I've mastered dismounting and mounting from the left pedal (similar to getting on/off a horse).
That is, when I'm ready to get off, I slow way down, stand on the left pedal and swing my right leg over, stepping down and squeezing the brakes simultaneously. Gotta lean the bike to the right as I'm legging over to avoid over-balancing to the left.
Mounting is the reverse: Stand on the left pedal, lean the bike away (to the right) hit the throttle (always, always, always in PA 1), swing over and go.