When I was a kid we had these old scooters. Made from an old fruite crate, 2 x 4 and old pair of roller skates. Nothing to sit on so that was not an issue. That’s all there was to it, stand on it with one foot and push with the other foot. Drag one foot to stop.
Recently I bought an old Sun EZ-3 recumbent trike. One of the many benefits of a recumbent is the nice cushy seat. It’s been described as riding a reclining lawn chair. But have you seen all the things they have now, in the name of exercise, that you don’t have to sit on.
This guy doesn’t have to worry about getting a sore bum.