how about something like this:
The Automated Safety Hitch | Trailer Hitch | Gooseneck Horse Trailers | 5th Wheel RVs | Flatbed Goosenecks | Fifth Wheel
there used to be something similar called a tow-buddy, but I couldn't find anything current on it.
That dolly may be pricey, but when it comes time to move on it would presumably have some resale value, while a big ugly extended gooseneck hitch on the back of the coach may make it pretty hard to sell, not many buyers would want that.