Page 270 of the owners manual says
"Your vehicle is not designed to be dinghy towed (with 4 wheels on the ground) behind a motor home."
"To avoid serious damage to your vehicle
Do not tow your vehicle with 4 wheels on the ground"
Remco may have a solution as suggested by TXiceman, give them a call.
2013 Toyota Highlander | Owners Manual
__________________
US Navy Vet, Liberty Tree Member of Oath Keepers, NRA & VFW Life Member, Alaska EMT.
2009 Safari Cheetah 40 SKQ
2009 Winnebago Chalet 231CR