[wingnut60]

$6200 is not an unreasonable cost for an Onan 5500 completely installed and wired; may be a little high if the unit is already gen prepped. IF the unit isn't prepped, be very careful that they do it all correctly--when shopping replacements for my old Suites, had 2 dealers and a gen shop that declined to give me an estimate and all recommended not to do it if not prepped.
Having it on a rear carrier can usually work well if the carrier is well-built and stable.
In the tow truck will work good also, if you have the room and the fiver won't contact it when turning.