Thank you all for your innovative suggestions. As DH says, there is a solution. We're leaning toward the standing lift; he is an above the knee amputee w/o a prosthetic. Until last year, he got around via wheelchair and crutches. He's no longer able to use the crutches and therein lies the real challenge. He would be able to transfer from the mobility cart below, stand on the lift, and get into the wheelchair in the trailer. (In the past, he would have managed the stairs on the crutches :)) We're waiting to hear from Forest River regarding recommendations on the installation of the lift on the fiberglass structure. And, of course, there is matter of the cost involved with all that. Nonetheless, we've reserved a site at a state park here in FL for a week mid-January and we're happy and excited to get out there and do it! Again, thank you all, I'll report back with the final solution.
Wishing all a very happy, healthy and prosperous New Year traveling along your roads of adventure.