I think you can gently heat (heat gun, not open flame) the stickers to soften the adhesive, then pull them off. The chemical products will then help remove the remaining adhesive. Be aware that the paint under an old sticker will often not match the surrounding paint because of of sun fading, etc.
My 2 cents.
Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.