Having done this several times, here's my recommendations:
DO NOT use a razor blade to remove the stripes. You'll scratch the gel coat. Use a heat gun (very carefully) to soften the vinyl and use a plastic scraper. Acetone will remove the final bits of glue and vinyl. I use a heat gun made for the shrink coverings on model airplanes - it's $23 available here:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJD39&P=ML. It doesn't get as hot as a paint stripper, but it's a lot hotter than a hair dryer.
For the ultimate finish, flip the boat upside down and fill all the scratches in the bottom with polyester filler (Formula 27). It's a grayish-white, but since these are on the bottom, you probably won't see them. Sand the hulls with progressive grits of wet-or-dry sandpaper (wet) 320-400-600-800-1000 (the higher/finer grits are available at auto parts stores).
Using an angle buffer (also available at auto parts stores), go over the entire boat with 3M Heavy Duty Rubbing Compound. Wipe off all the residue, then go over the whole boat with 3M Finesse-it II and the angle buffer. By now, you'll be seeing your reflection in the finish. A couple of coats of 3M Boat Wax will seal the gel coat and prevent it from absorbing stains from the water.
Depending on how deep the fading goes, you may or may not bring back the original color. And of course, this will not work on the non-skid (I usually tape off the non-skid to prevent damage). If you want a painted finish, use a one-part polyurethane rolled and tipped out with a brush after the 1000 grit sanding.