I've seriously considered going this route a few times, but have always decided against it.
Main reason being: I just do not trust the RV ladder to safely handle that weight when on the road for any length of time. Yes, an RV ladder is designed to handle 2-300 lbs of load. However, it was designed to handle a STATIC load of that amount; they are NOT designed to handle a DYNAMIC load of any kind. Dynamic meaning, a load that bounces, shifts going down the road. Doesn't matter how well you strap it down, its still a dynamic load, not a static one, when the RV is going down the road.
I know there's lots of folks will post on here that they do it and it works fine for them. It may well work OK in some cases if you limit it to just one small bike and strap it down real good. For us, though, when I think about the things that could happen if you lose the bike and 'launch' it back at the people on the road behind you..just ain't worth the risk to me. I prefer to keep all our bikes on the towed vehicle, anyway, as there are times we want to take the bikes places we'd go with the toad, but would not want to take the Motorhome.