1968 Silver Streak Continental Rocket Interior Skin Question

Hello, I am brand new to this! I just bought a 1968 Silver Streak (Continental Rocket) and my brother is helping me reno it. (He's the handy guy with the tools!) Before we start disassembling the interior I have a question about the interior skin. Do most people carefully remove the skin (we want to better insulate it and it needs some rewiring) and then reinstall the interior skin and paint it or do you buy new interior skin? I am on a budget (aren't most people) and want to make sure we do this as correctly. What kind of insulation do you think is best? We haven't touched anything inside yet. I would be most grateful for your advice! Thank you! ~ Rocket Cramer