Maps... Yes, maps... Seemingly a simple, and helpful device when trying to get from A to B... Let me relate a couple thoughts on maps, generated via my trip north...
1) the AAA map of Maine sucks... They managed to label a couple interstates wrong. Hello, how do you not get that right?...
2) because of 1) you should stop and buy the Maine Atlas at the DeLorme Map Store... It was excellent, and seems like they got it right.
3) When you get to MDI, you will find that there is no single map that will cover your needs, unless all you want to do is drive the loop and get back off the island. After much looking, the best map we were able to get of Bar Harbor was a photocopy of a single 8.5 x 11 map that listed the main streets. I find this hard to accept, but that seems to be the case... You will also need your bus route map and schedule. Finally you will need a trail/carriage road/highway map. The one I found the best was from National Geographic. There was a much smaller one printed on Tyvek that would be ok if you need to save an ounce or two, but the Nat Geo map was nicer...
4) When marking you route on a map, choose a marker that is transparent such as a highlighter... Using a sharpie will only annoy you later as you attempt in vain to read something you obliterated with it.
5) When reading your trail map, pay attention to how close the topographic lines are to each other... Close means steep... Somehow I managed to miss that concept before coming down the West Face Trail...
As a side note, and random observation, DeLorme doesn't make a map of MDI... Um, Hello?... They're based in Maine... Most people going up to MDI will stop in Freeport along the way... How do they not figure out they should make one?... Yes they had the Tyvek one, and the National Geographic one in the store, but why not their own?...