Pallets and Foamie??

I am in the very beginning stage of building a teardrop, in fact I don't even have plans or a trailer yet. I'm thinking through my head what I'd like for the outside and have the idea of using old pallets over the foamboard then my inside board of I'm not sure yet.
What would be the best way to secure all three layers or is this even feasible? For my interior, I'd like to eventually use maps as my "wallpaper.
Or is this just a crazy thought?
Thank you for your thoughts and comments.
Debbie
What would be the best way to secure all three layers or is this even feasible? For my interior, I'd like to eventually use maps as my "wallpaper.
Or is this just a crazy thought?
Thank you for your thoughts and comments.
Debbie