I think I will jump back onto the Airstream Forum as I am planning on returning after having a huge motorhome for over three years.
So, I towed a 2007 25' International with a 2005 Porsche Cayenne Turbo (450 hp, 460 ft lbs torque) and while it had adequate power the issue was downshifting from 6 to 5 on any little hill. Maybe I needed to just hold it in 5th????
So, I bought a 2008 Dodge/Cummins 2500, Crew Cab, Long bed and the 21 feet of truck pulled my 2009 International 27FB with no issues. I think I got about 14 mpg towing about 60-65 mph. The Dodge has about 70,000 miles now, and it is waiting for me to sell the motorhome and get a new Flying Cloud 30.
I towed my 27FB from North Carolina to California, into Idaho, through a blizzard in Wyoming, and a couple times to Texas.
My opinion is, if possible, get a diesel tow vehicle. The low end torque is so nice, especially in mountains.
And, I look forward to being back in an Airstream......
Happy trails and Good Luck
Ms Tommie Fantine Lauer, Greensboro, NC
AIR #31871 WBCCI #4165 K4MTL