We try to make it up there every year or so, usually in September for "Open Lighthouse Day" (second weekend in September). This year we are doing the Grand Slam Lighthouse Tour (17 lighthouses by boat) 7/30/16. then we'll do the self-guided tour of Acadia NP. If you haven't done it before you really should, get the CD at the welcome center best $12 I've spent. While I was listing to the story I kept thinking "I know that voice", I looked at the CD case only to find out it was an old friend I was in the Camera Club with years ago (small world).
Here's a link to it:
http://www.barharborwhales.com/whale-watching-tours/lighthouse-and-national-park-tour/