Decided to let it pass
Thanks everyone for the great advice. In the ensuing madness that the time frame of a CL sale allows, along with doing my homework of a ton of ideas (trailer, RV, school bus, etc) and coming up with one of the fastest budgets I've ever accomplished over beers at the bar I told the seller that I was letting it pass.
I think for the aim of a tailgating rig the nostalgia of an Airstream was a big pull, but from what I've read around here they can be a touch on the pricey side to fix up to the point of beginning of specific build out.
This doesn't mean that I've passed on the idea altogether but merely that we decided that we needed more time to get our plan under us before we part ways with many thousand dollars to start this project.