When it comes to stretching vacation dollars, free is key. The usual choices include visiting parks and preserves, local historical society museums and public gardens, attending community concert series and finding swimming holes, but there are other possibilities. Here are 10 places to go and things to do in Maine that should get the mental wheels spinning on how to put more ''free'' into your vacation. Do note that, while not re quired, a modest donation is accepted at most.

— Hilary Nangle, Globe Correspondent