Not sure where Gardiner is, and these places are a hike from Kennebunkport, but we really enjoyed Mt. Desert Island (Acadia National Park, Cadillac Mountain, the Asticou Gardens at Northeast Harbor). Frenchboro is another great island to visit (ferry from Bass Harbor). There's a place called Lunt's on the dock that always had great seafood, all caught fresh.
Rob & Kelly, Bella & Brady (Miniature Schnauzers)
2016 Eagle 323LKTS
2016 Ram 2500 6.7L CTD
2015 White Hawk 29REKS Summit Edition (Traded)