Voluteering, if you don't mind little bit of mild labor, is a hoot. We have been doing it over four years now, for several states parks and two different federal agencies, and are having a ball. Gives us a place to park for free, in exchange for a minimal amount of labor (one state we have worked for only reguired 14 hours a week, for both of us! We gave lots more than that, but 7 each was the requirement). When we are not dragging our home on wheels around we actually get semi-decent fuel mileage, and our only real expenses are food, which we would have anyway, and entertainment. And we entertain pretty cheaply. We meet lots of intersting people, get to see parts of the country we could not afford any other way, a win win situation for us...