If it's 56 inches, I would doubt that it would fit, but it might. Rangers don't have big beds. At 56", the cab is 8" wider than a 4x8 piece of plywood or drywall. I seem to remember that neither would fit flat in a friends Ranger. But what the hell, at my age I'm lucky to remember that incident at all.

Maybe Tech's way would work if you can get it strapped down well enough. Or if you ain't got an old mattress, maybe a rental trailer might be best.