Picked up a low mileage Class B for my sons to use a few months ago. 2001 chassis and 2002 coach with only about 15k miles on it. Was kept in a garage and really not much rust other than some surface rust.
I noticed that the brakes seemed a little mushy and stopping distances were longer than I liked.
Took off the tires a few days ago and this is what I found:
Even though it was kept in a garage, the rotors still pitted. With that much pitting, your surface area for applying friction from the brake pad was probably cut in half which in turn makes your stopping distance longer.
So if you have an older coach that is not driven much, don't think that you can wait 30,000 or more to check your brakes and rotors. Do it now so you can stop quickly and safely in an emergency.