Peeling decals is indeed a daunting task. It takes a lot of patience, some heat and a lot of gentle scraping with a plastic putty knife or a wood or plastic blade (a metal blade will likely scratch). Permatex and 3M make decal removal chemicals that may help too.
Then you have to figure out what to replace them with. The finish underneath will be a slightly different color than the rest of the coach, and there is almost zero chance that replacement decals will be available from the manufacturer unless the rig is nearly new. Having new stripes painted on is the best solution, but rarely inexpensive.
2004 American Tradition; 2013 Buick Verano
Homebase in the Ocala Nat'l Forest near Ocala, FL