The girls and I rose early (they didn't sunrise with me, but rose shortly afterward) to hit low tide at Bar Harbor, so named because at low tide a large sandbar is exposed. That bar provides access to the first of the Porcupine Islands. We (V) played with dozens of sea snails on the bar, we checked out rocks and shells, and we walked across to the island and explored. We found a ruin that reminded me of Knapp's Castle back in Santa Barbara County. Must have been a spectacular place to live in its hayday.
We drove to the top of Cadillac Mountain, the highest point on the Atlantic Seaboard, then hiked around the rounded peaks for awhile before heading down to explore Bar Harbor at high tide.
This park is definitely worth a lengthy visit. Many thanks to the cycling traveler who directed us to Blackwoods Campground.