Old coach smells

Fabreeze on the stuffed furniture and Fresh Wave in the living spaces.

I would look for a water leak. Make sure your roof is well sealed and there is no delam around the windows.

If you have slides look at the bottom of them (where there is carpet) and check for moisture.

If you have an infrared heat gun shoot the walls looking for a warm spot. This will indicate something growing in the wall. There will be some form of rotting going on.

Your coach should not smell "like an old coach." There is a problem.

Try putting a plate or two of baking soda in there. It's supposed to absorb the stink. I'm not so sure how well it truly works, but can't hurt to try.

could be mold your smelling.

Run a dehumidifier and see if it helps.
Or a Ozone generator.

Kinda "musty" ? Open the windows and take it for a ride. Get the air circulating.

Your description of "old coach" really doesn't help much...except to me, it means non-use.

FWIW.