I'm planning to give out sample magazines starting this summer ...
I've noticed that Airstream folks LOVE pins. It would be very cool to have some sort of neat Airstream pin to give. See www.pinsource.com
You could carry a Polaroid and shoot pics of you & the hosts standing by your trailer -- to appear on their refrigerator or scrapbook.
We also sometimes give people little nip-sized bottles of maple syrup. $1 each from our local shop (mail order house Dakin Farm). This is more because so many people don't know good maple syrup from the fake stuff -- it's our obligation as Vermonters to educate them!
And little food items are often appreciated. I've never seen anyone turn down a pint of Ben & Jerry's!