A campground neighbor in a class A did the removal job on the front of his cab. He used Goof-off, plastic scrapers, heat gun and other tools that i don't remember. The vinyl on his rig was huge, maybe 4'x8' and he spent days doing it. The finished job looked good, almost like new. I'd guess it took him 20+ hours.
He was lucky compared to our Class C's, he was standing on the ground or sitting on a chair the whole time. We would have to setup a scaffold of some type to be able to do the nose over hang, doing it on a ladder would be murder. He told me that there are solvent listed on the web, but he didn't use them. Maybe hang out in a body shop and see what they use.
My 3011DS 2018 has a few dings and bug juice stains but nothing bad yet. I believe that the black stains under the vinyl are mold and the small dings allow some moisture to get under the surface and start growing the black stuff. I wax the nose very well 3 or more times a year to seal it and I bought a long handle truckers squeege that I try to use daily when i'm on the road to get the critters off before they bake on.