Whenever I go cyclotouring, loaded with panniers and camping equipment for long journeys, I'm treated like a Barnum & Bailey roadside attraction by a lot of very very nice people in any state parks I visit. I get a lot of them coming up to me and striking up conversations when I'm relaxing at a picnic table somewhere out there.
I can't really think of a single comment that was any better than the others, but the conglomerate "I think what you're doing is so neat!" that I frequently get is always my favorite thing to hear. I do aim to inspire interest in travel-by-bike, and it's infinitely better when I can do so by example, without getting on a pulpit about it.