Want to Buy Camper for F150 Raptor

I have a 2017 Ford F150 Raptor 4-door crew cab. I am looking to get a camper to enjoy the summer. Ping me if interested in selling.

Question:
For those of you who have an F150 crew cab, what is the correct measurement of the bed? I get 5’5" and 5’7" depending on where I start measuring. Thanks for the help.