I just removed mine from my 2007 coach. Mine was in pretty good condition but was starting to get blotchy in a few areas so I decided to get it off before it got bad like some I have seen. I can only tell you what worked for me.
I let the sun warm the front of the coach and, using plastic razor blades, lifted the edge. Once the edge was lifted, I was able to pull it off in fairly large pieces. Pull slowly and at an angle. I tried a hair dryer and heat gun but the warmth of the sun worked better. Once off, I used mineral spirits to soften the glue, scraping off most of it with the plastic razor blades. I finished up glue removal with lacquer thinner and a terry rag. It is a lot of work and takes time but my paint under the film was pristine.
2019 Grand Design Solitude 384GK 5th wheel. Glen Allen, VA