First thing you need to do is to bring your truck indoors or wait till a warm day to remove it, since its easier to remove if the adhesive is warm. You could also use a hair dryer or heat gun (on low) to gradually warm up the trim and try to separate it from the adhesive. Take your time here, or you could lift the paint with the adhesive. Heat the trim a bit, test to see if it will separate, heat some more, etc. Dont worry too much about removing all the adhesive just yet, because theres a solution to that in the next part.
Once all the trim is off, then you need to remove the left over adhesive. 3M makes a tool called a "stripe off wheel" that goes in an electric drill and acts like an eraser to quickly remove the old adhesive. I used one on my trucks stock pinstriping and liked it alot. Once all the adhesive is removed, then its just a matter of buffing out the paint so it all looks uniform.
Its not a tough job, its just time consuming and takes a bit of patience. Good luck!