I can now speak from actual experience towing the 25 FC with my 2009 Ram 1500
. I have towed it about 1500
miles now. The truck has a strong 5.7 liter V8 and has sufficient power to handle the job over some pretty good grades in western PA. The key with this is the Tow/Haul mode, it makes it all possible, the proper shifting and engine braking under load is great. The Equalizer hitch makes it very easy to tow an Airstream at highway speeds with merging not a problem. I averaged about 11.9 miles per gallon towing.
That being said, if I had the money, I'd probably get a 2500 diesel to do the job.
I wouldn't want to try to tow anything larger than the 25 footer with what I have.
So far, the Dodge Ram 1500
did everything I asked it to do without a problem.