Freebird 1977 Dodge CB300 Tioga II 16' Class B or Class C

Only 16'6" 318. Single rear wheel. Rear door entrance. Wet Shower. B or C? Thinking about towing med-size SUV 3,200 pounds. U Haul rents a 10 foot single rear axle box they claim tows up to 6,000 pou...