Make sure you get a good paint on before the rhino liner. I don't think that is intended to go over bare metal. If you do get a scratch in it, rust can spread under the liner. I'd use something like POR-15 or zero-rust or a good 2 part epoxy primer with top coat.
Sounds to me like you have every intention of selling...but what do I know? Limit the Rhino to the size and shape of the original tar. Pics help, obviously you're going for every possible dollar if you do sell, so any documentation is a plus.
I would think hard about the rhino lining or any others. The truck you have is clean and virtually rust free as I recall. The key to the rust issues is to get everything down to the base metal and then start with a good two part epoxy etching primer.
I really think that if properly prepped, painted and finally cared for the truck will stay rust free. I also lean towards staying with the stock look. TLC seems to really lean towards the Linux (sp?) system and they get the resale value from them. (They are also running with a proven reputation)
In regards to the undercoating, I have been told that there is new undercoatings with rust inhibitors. If you do Rhino the interior I would color match it and then do the underside in the black.
I do agree take a ton of pics of before and after. Take pics of every nook and cranny. As the story goes "pictures tell a thousand words".