We have used YankATank Hitch Mounts for years. It keeps our truck beds empty while still allowing us to keep the YankATank onboard whenever we need it. (Just remember to take 30 seconds and pull the dollies off before going back on the road.)
YankATank Hitch Mount
$295.00
Hitch Mount goes in 2″ receiver hitch to transport YankATank on back of vehicle as shown in picture 2. (YankATank and truck not included.)
YankATank dollies should be removed when transporting. (Removal and attachment takes a few seconds)