My wife found a Mercedes Sprinter SWB (118" WB). She thinks it is a Sportsmobile. How can I be sure. It's in good condition, 130k miles, twin beds, shower, porta potti, small sink, 110 hot water heater, 110 fridge. 15 (?) gal fresh water tank, 20 (?) gal grey water tank. Sink drains to 5 gal jug. House battery under the passenger seat.