If you're OK with working on various mechanical things around the house, working on your RV furnace isn't that big of a deal; they are very simple in design.
Two years ago, I fired up my furnace in spring for a fishing trip; worked fine but didn't have to use it on the trip. Later that fall I needed it, and it seemed to only put out about 1/2 the heat we were used to. Upon returning home, I pulled the unit out and took it apart on the bench. Turns out that a small spider had made a home in the burner spud and it was affecting gas flow. Took it out and blew it clear and put it back together. VIOLA! Worked great. Good thing it did, because the next weekend was very cold during our Halloween camping trip at the state park. Really glad I did fix it. In fact, it was far harder to get the thing out of the RV than it was to fix it. Had to take the stove out to get back behind the counter and down to the furnace. What a PITP (pain in the posterior).
Two years ago, I fired up my furnace in spring for a fishing trip; worked fine but didn't have to use it on the trip. Later that fall I needed it, and it seemed to only put out about 1/2 the heat we were used to. Upon returning home, I pulled the unit out and took it apart on the bench. Turns out that a small spider had made a home in the burner spud and it was affecting gas flow. Took it out and blew it clear and put it back together. VIOLA! Worked great. Good thing it did, because the next weekend was very cold during our Halloween camping trip at the state park. Really glad I did fix it. In fact, it was far harder to get the thing out of the RV than it was to fix it. Had to take the stove out to get back behind the counter and down to the furnace. What a PITP (pain in the posterior).