the rack can be adjusted so that you do not have to move the support bar up and down for setups. The bunk end should slide out over top of the bar.
'course no getting around taking the bikes off.
There are pads that attach to the back wheels to protect the roof finish and assist in keeping the wheel from sliding. You also do need to use the straps on the bike to keep it from bouncing around under way.
2016 Roo 21SS, 2016 F150
2015 Rockwood 2514G (pup), 2015 Fd Expl,
2003 Coleman Utah (pup), 2007 Fd Expl