Hi
Not sure if you are asking about putting a roof rack on the ridgeline roof or the top of a topper.
I put a stock rack on mine and haul a 16 foot Nova Craft. installed webbing tie down under the hood near the windshield and use the forward tie downs in the bed. The stock rack only has about 4 foot from the front to the back at the farthest spacing, so not optimal, but I would have no problem going any distance with my set up.
M