FWIW, I have a 33' 7,600lb trailer and it's a bit much for my Expy Max w/HD tow. Power is no issue, but crosswinds and passing trucks push me around more than I'd like. I upgraded to a ProPride hitch, LT load range E tires, and Hellwig sway bars. It's better but not great. I'm waiting on Bilstein 5100s to arrive to see if those help (I've had 6 leaking factory shocks in 40k miles). I've been to the scale and my tongue weight is just under the 900lb max.
Molaf, I think a 26' 7,000lb trailer would work well with the Max. There's less surface area to be affected by wind and you can go to a higher percentage tongue weight than I can. I tow through the Appalachian Mountains and haven't had any issues. My transmission heats up on steep, slow inclines, but it's never overheated. Engine braking works well in most cases. I did go down a 14% hill that made me nervous, engine braking in 1st gear and still riding the brakes. But 99% of the time there's no problem. Honestly, I've had more issues with winds in the midwest plains that I have in the mountains.