I bought a Stromberg Carlson Bike Bunk. Then use a 4 bike rack on it. The kind rack that the bikes sit on, not hanging for obvious height reasons.
Bike bunk:
https://www.etrailer.com/RV-and-Camp...RoCYK0QAvD_BwE
This is the bike rack I use:
https://www.etrailer.com/Hitch-Bike-...an/S64665.html
Traveled well over 3000 miles with four bikes on it.