Welcome Ron. I think you've got a good idea with the heat gun. I've had to repair some cladding damage as well. It doesn't take a lot to soften the plastic. Since I had a woodshop handy I used a bandsaw to cut a quick rounded guide for the curve, and once the cladding was slightly soft from the heat I nudged it back into place with the wood guide. Its definetly easier from the inside of the cladding. You probably know, but plastic goes from being soft and maliable to melting into a gooey mess fairly quickly.