The trailer is a 1992 21ft Sovereign
with a dry weight of 3,900 lbs. We looked at the Sport 22 and compared the 2, the 21ft is the smallest trailer that Airstream built with twin axel, it also has the same holding tanks as a 30. It has a large shower and a nice couch. Towing in the mountains is not a problem, we have been on Interstate 40 a number of times, you forget the trailer is back there. The mileage drops to 15 to 16 mpg. The Sprinter is a 2006 model 2500, what's nice is that it does have a generator and boondocking in hot weather is not a problem with a/c and we stay is the trailer in cold weather. If one of us get cranky we sleep in separate units. Most camp sites have a 30 & 50 plug in so both units can be hooked up. It's a good combo, also the sprinter is a good run around town vehicle and fits in parking places at Walmart etc.