Well, it's not an RV and kind of a specific application, but since you haven't heard from anyone else yet, I'll share the single experience I have...
Last year I had two bucket seats in a 1967 Mustang recovered. I provided the seat covers, removed the seats and took them to an auto upholstery shop in northern California. Cost to perform the work was $250 per seat.
2018 Coachmen Crossfit/Beyond