The class C I sold to Dylan, well let's just say it was adequate at towing my heavy trailer (22' heavy frame with two 7200 lb axles, with my 6K plus Jeep, two full size truck tool boxes, a 15 gallon fuel cell, winch, battery, spare tire for the Jeep, two trailer spares, and two large coolers. Flat out, it towed at what ever speed I wanted it to go, hills... yeah, it slowed down, but it didn't kill it. The Triton V-10 didn't mind the RPMs it had going up hills lke Old Fort mnt, or the big one on I-26 headed to Harlan or, the big one in Va. not too far from KY headed into KY. It kept 50 MPH unless traffic made you lift, and that, well, it killed it.
The one thing I'd do if I were to have another one, would be to build a shed to park it in. They just are not made (at least the one I had) to sit out in the weather. After I sold it to Dylan, there was a lot of water damage that he found that I was unaware of. I had fixed/patched a few places, but it was all over it, not just where I had patched it.
But towing wise, It towed nearly as good as my 3500 chevy I use now. If you could find a class C with the 8.1, well, that would be ideal! I really miss my old 2500 with the 8.1 and allison trans.