We have a friend that recently had both knees replaced, and she finds the mentioned "butt bump" method the easiest way to handle our steps when she visits.
When my wife's disabled sister traveled with us some years ago, we used a large dog 250 lb capacity ramp and a narrow travel wheel chair to move her in and out of the coach. Later on, when our then wheelchair bound teen aged granddaughter traveled with us, we used the same ramp and chair for her as well. The bigger problem for us was getting them in and out of the shower. I modified a shower bench to fit, but I couldn't find any practical way to use anything like a Hoyer lift in the tight confines of the bathroom, leaving us with a looped strap over my shoulders under their butts as the preferred method of lifting them in and out.
Dutch
2001 GBM Landau 34' Class A
F53 chassis, Triton V10, TST TPMS
Bigfoot Automatic Leveling System
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox baseplate