One advantage about 5th wheels is all the steps is on the outside!
Not sure if you're able to, but the easiest way would be to retract the steps. Then lift him up from behind his front legs (so he can get his footing on the floor), when he's in the house / cabin / whatever you call the interior? .... after which it's all down hill cause all you's gotta do is push the rest of him in-side!
I couldn't do that with our Eagle (because more then half the steps are in-side), so I use to help Harlee up by pushing / lifting her from the behind.
I bought a folding aluminum ramp for her, but there was no way she'd use the dang thing. So I got an aluminum ramp in the storage bay for Calvin when he'll need it. But it'll be more then likely that I'll be doing the same with him as I did with Harlee.
Good Luck!
Pops