How fast do you fellow class Aer's drive? If you have good road conditions and are towing, how fast would you go? I am new to class A's, Very comfortable driving, My last trip I was averaging about 61...
mTrumpet's answer is the best. Each coach type has a sweet spot where it just feels right. If you push past, temps go up and things start to mumble. I know people that run at 75 towing when they can and claim that's where the coach is happiest.
Running 55 on roads posted for 65 and greater will not make you any friends. Just sayin'.