I'd go with bedliner. I had mine all done with LineX and pulled each piece off and had them encapsulate the cladding. It doesn't stick well to the type of plastic, nothing does so it's sprayed on both sides with the texture only on the outside. I also used some off the shelf stuff from the auto parts store for my hood insert and it turned out great. Don't know how hard it would be to do all the cladding with that stuff though. If what ever is on your cladding now is coming off then what ever you spray on to that will come off with it. I'd do the LineX if I were you.
There's no 'I' in denial.