Potter, sometimes you have to think outside the box...er silver tube.... Consider buying a unit and then reselling it. Larger AS's are going cheaper than small.
You may also find a Park Model trailer of the SOB type easier than an Airstream.
Remodels, be they home or trailer, always go on far longer than expected. Ask anyone who undertood the job lately how long they planned, when did they "think" it would be completed. Plan for three months longer than what it will take.
1984 28' Funeral Coach
Former Rolling Showroom & PuttLab (now party bus)
"I'm not an expert. But I did sleep in an Airstream last night."