Much depends on the length of the bed..... pin placement......length of extended pin box.
I've found a longbed with the pin 3-4" in front of the trucks rear axles may need 6"-7" clearance so the top of the bed at the rear doesn't get into bottom of the trailers overhead.
A short bed truck with the pin zero over the trucks rear axle and a extended pin box may get by with 5".
And of course camping in the bojacks over all kinds of terrain vs glamping in RV parks with all paved/level/flat roads and parking pads make a difference in the amount of clearance needed for a particular truck/trailer combo.