When we had a BF in a Chev, I tried several options to get the height correct. The best solution I came up with was heavy, 1" rubber livestock mats. Downside is they are heavy. The upside was the needed height, a bit of extra cushion for the bed and camper and good insulating properties. Even after we sold the Bigfoot, I just left the mats in the bed (until yesterday). It took two mats and a sawzall to make the cuts for fitting nicely in the bed. Only removed them because out new camper (non Bigfoot) doesn't need the clearance and I needed to loose some weight.
