Need more information as to what kind of coach you have whether it is diesel or gasoline.
I have a diesel so I will put in my 2 cents on what I have discovered is best for my engine. First of all I have a Caterpillar engine so I stick with fuel filters that are manufactured by Caterpillar. Now on the air filter is where I decided to leave from the original air filter which was a Farr filter. Reason was that the vacuum gauge was showing that the vacuum line was either plugged up or a dirty filter even though the filter was brand new. So I decided to switch to a Racor air filter, and wow what a difference in power and the vacuum gauge is working properly now.
The oil filter I purchase from Napa. They sell a cheap filter and an expensive filter. I purchase the best they have. I believe it is around thirty dollars for the filter, but I could be wrong since I hardly ever notice what items cost.