What's the hitch capacity of your RV? A conversion van is pretty heavy and would require a beefy tow bar, base plate, auxiliary brakes, etc. In addition, most every conversion van is an automatic transmission and not many automatics are towable 4 down, so a drive shaft disconnect might be an added expense.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI