uh...
OP, your ambassador is a diesel pusher, on a Monaco RR4 chassis.
It has drum air brakes on all 4 corners.
I would be EXTREMELY concerned that only one brake got hot. For sure have that checked. Possible to probable that you have problems with the automatic slack adjusters, they are supposed to keep the drum brake adjusted.
"POSSIBLE" as well that your rig only has effective brakes on that one wheel!!
Are you using your "engine brake"? There should be a red rocker type switch, probably on the drivers left. Use it whenever you are in traffic or going downhill. turn it off when you are cruising. It will help a lot.
Also, (and my memory isn't perfect on exactly what year Knight/Ambassador changed to the rr8r chassis from the rr4.) rr4's have a known problem with the trailing arms on the rear suspension cracking. This is serious if it wasn't repaired. It is something you should check.
If you look directly in fron of and behind a front tire and see air bags, you have an rr8r and nothing to worry about.