I have owned a sign shop for the last 13 years and have done a lot of stripe and graphic replacements on RVs. The best way we have found to remove old stripes was using a heat gun and plastic scrapers to first remove the vinyl and then go over the left over adhesive with rapid remover. This stuff works the best of anything we have found. I have included the description from our suppliers website. The stuff comes in quarts and gallon sizes. Our cost for a quart runs around $20.00 and a gallon runs $65. A typical 35' Montana 5th wheel would use about a quart of product. I am not selling the remover just letting you know the cost involved. Maybe check with your local sign shop to see if they have any for sale.
Just my 2 cents.
An environmentally friendly product, great for removing adhesive left by decals and vinyl graphics. Rapid Remover is a non-toxic, water-soluble methanol based solution with a mild citrus odor that breaks down and removes adhesives fast. Spray it on, wait thirty to sixty seconds, and easily wipe it off with a plastic squeegee, with no damage to painted or bare metal surfaces.