Dave has drum brakes on his bus. Even with proper maintenance, they are VERY easy to let the smoke out of. We always wanted disc brakes on our bus. That would have been awesome.
With standard drum brakes, it is tough to stop on a 6% grade. That's why slow is the key. I agree with you, Dave. I like interstates. I will go out of my way to stay on interstates, if needed.
I have been on almost every interstate in the country, and my previous coach as well as my first coach had drum brakes. I have been on I-26 a lot because I live in Knoxville. My last coach weighed 46,000 and we have always towed our 6700 pound Hummer so I know a little about managing energy going down a hill.
I still maintain that the brakes are not only fine for the job, but on a 6% grade from 55 MPH you can stop a coach. But for normal descents as I stated above don't pump the brakes and give up air pressure. And keep your target speed in mind, and when you reach it apply firm braking until you are about 10 MPH below target, release the brakes to allow them to cool and be ready for the next brake application when needed. The key is the target speed and letting that speed be the max speed for the gear you are in.
If I choose 55 as a target, I need to be in 4th because its top speed is 55. That way I am getting the maximum benefit from my selected gear and I am not abusing my brakes.
And do not ever be intimidated by other drivers. Screw them. If you let them push you then you have only your brakes to separate you from a very nasty crash. Choose your speed and let everyone else go around you if they do not like it.