I've always used the heat, and GooGone method. Heat with a hair dryer, pull of the graphics, then apply GooGone, let it sit for awhile then wipe with a cloth with GG on it. I found, to keep using a clean part of the rag for the GG works best.
There is also the friction method, see this link. In your case this may be your best alternative. http://www.rvsg.com/restripe-removal.asp
You simply apply it with a natural brush over the graphics and wait 20 minutes or so. After the product eats into the vinyl, it then works on the adhesive below. When all soft you gently push it aside.
After I used RMP on ours I did not want to remove them. The edges are still damaged looking if you are close enought to touch them but the color and shine make them look new like from where most people view them.
I ended using GraphXOff (yes, I am a procrastinator) and it worked very well. Brushed it over the graphics, waited a few minutes, and scraped the gooey remains off. Some of the graphics took longer to soften up than others, but they all came off with relative ease. The only thing to watch out for was, the chemical does soften the underlying paint somewhat, and I had to be careful not to gouge the paint.
Thanks for the tips!