You mention a 5th wheeler with a 22' long garage. That's quite a bit of space out of the length of a 5th wheeler! If you look for a Class A toy hauler, you could use the garage for the motorcycle(s) inside and tow the other vehicle 4 down or even on a dolly if needed. Most states limit length to 65' combined length, although seldom does it become an issue unless an accident draws attention to the over-length violation. Also, most 5th wheelers aren't built on frames beefy enough to add a class 3 or higher hitch on the end of the frame. It would be subject to pretty serious 'seesaw' motions over the extreme lengths behind and in front of fulcrum points of the set up.
Only some states allow 'triple towing' (I know, it's 2 trailers, but it's called triple towing)
and most of those states are in the west.