I have a 2011 f150 with a 5.5' box and a new otter pro cabin. The house fits perfectly in the back of my truck. Just make sure you tuck in the canvas every time you fold your house down otherwise it will be difficult to shut your tailgate.
2016 F150 Crew Cab with the 5.5' box, Otter XT650 Cabin. Like Derek says, just tuck the fabric in when you collapse the house. Fits perfectly with the tailgate shut. I can also close my Access cover on top with no issues.