I look at the braking thing a bit different than Chris (PAHunter). The truck has it's own brakes that should be capable of stopping the truck at it's max weight. (around 14,000 for my dually). The trailer has brakes that should be capable of stopping the trailer. Stopping, just like starting, takes longer than a regular car. You can't jump into a combo weighing 20,000+ lbs (23,000 in my case) and think it will accelerate and stop like a Camry. As long as you keep that in mind and maintain reasonable distance to the vehicle in front, stop and go isn't that stressful.
I'm with H&H818 on the mountains. Most diesel trucks today have some type of engine braking. My Ford does a pretty good job using the transmission and engine braking to maintain a speed going down 6% or higher grades. For those that been over Mont Eagle on I-24 coming into Chattanooga, it is a pretty good grade for East of the Rockies. The Southbound down hill seems a bit steeper than Northbound. I only have to hit the brakes a couple of times all the way down the 6% grade going into a few of the corners. The engine braking does most of the work.
Even with all that, the concern that the engine may not hold a speed and then the brakes will fail is more anxiety producing to me than rush hour with the trailer. There are people on this forum that will take much longer routes to avoid going over Mont Eagle.
Everyone has their comfort level. Take the route that makes you most comfortable and just factor in the time it may add. For some (my DW), the thought of towing anywhere is too much. That's why the Fort cabins are there.
j