It will fit with the tailgate down. I had an Avalanche and my Kodiak 450 would fit with the tailgate down no problem. I also had enough room beside it for the ramp, so I don't think the Raptor is too wide. The bed width is 50" I believe anyway.
Correct.. It will fit with the tailgate down.. the fenderwells in every chevy is 50" no matter if a normal pickup or not.. (they do this for us lumber guys who haul 48" plywood.) the raptor fits between the fenderwells of my fullsize chevy, so i see no problem, other than having to leave the tailgate down