1995 P32 Rotors Overheating

Push rod that seats against master cylinder piston clearance is critical. You might want to check into that, if the m/c piston isn't retracting quite far enough for venting of pressure on calipers, drag would be the result. Older medium duty truck applications typically had a adjustable brake pedal apply rod. Too much clearance you'd lose pedal, too tight brakes would drag. I went through about a gallon of brake fluid trying to get pedal on a old C-60 dump truck before I figured out the problem. Same deal on a old Ford bus chassis some time later, adjustable rod to master cylinder piston, brakes were dragging a little after rebuilding system, adjustment was very touchy..
I'm not suggesting OPs coach has adjustment but the way quality control can be, it's something to check into.