Can't wait to see how this turns out for you! are you gonna do lights on it also?
Something to help you in pep'ing: in the Settings drop down menu, there's an "Other Settings" option, there's a check box that says Hide a certain type of fold, basically the ones that assist when gluing. Unchecked that before printing and you will be able to make those slight creases to keep it from bunching up like it is in your photo.
Edit: if that's too confusing to understand, I'll take a picture for you later of what I'm talking about.
Welcome! I'm very interested to see how you do with this. Make sure to ask any questions, guys like Chernobyl troll these parts all the time and they have a heap of knowledge.
"Troll", you say? I prefer 'lurk' or 'prowl', 'trolling' has such negative connotations.
Regardless - this is an interesting project. Are you building the base form from Pepakura, with an aim to vacuum-form a clear copy later on?
Please follow the link for the gift of a grunt doing the peanut butter jelly dance