I added the Burr Handi-Lift to our 5th Wheel. The wall next to the door frame had to be modified to support the lift. I did all of the work myself after being quoted $6000 for modification and installation by a vendor.
The lift works well but the platform is too small for a wheelchair so I modified the platform to hold a transport type wheelchair. This is against the warnings of the manufacturer, we never had a problem with it.
If I had to do it all over again I would get a portable ramp and landing system to use instead. Or use a Hoyer Patient lift. These provide the flexibility to use the devices where needed instead of a fixed location.