I've done this (sort of) by bike, with a few other guys. No agenda, no destination, just a bunch of guys with bikes loaded up with gear up in the hills of Vermont, New Hampshire and Maine. We learned, quickly, to seek out and introduce ourselves to local law enforcement or fire services. "Hi! We're a bunch of guys doing a bike tour of the northeast - do you know of a place that will let us camp out for free tonight? Oh, and we could really use some water for our water bottles." The truth is ALWAYS the best approach. In every case, we were treated like guests of the town, asked about where we were and where we were going, and why we were doing it. One time, we were directed to a park, another to a church basement. One time, we ended up in a hayloft. All was fun.