casual everyday food is great at Rupununi's and Geddy's. Both right on main st. in Bar Harbor where the majority of the shops are. Stewman's Lobster Pound and Trenton Lobster Pound are always a good casual place for seafood and lobster. Bar Harbor Inn is nice if you are looking for something fancy. Jordan Pond House is a little place inside the park. It's one of my favorites to just go and sit outside, drink iced tea and just enjoy the beauty of it all.
We've done ocean fishing offered through the Bar Harbor Whale Watch Co. That was fun, but I have never done the actual whale watch. It can get cold out on the ocean so be prepared. Of course you said you know about the park. Hiking, Sand beach, drive to the top of the mountain, horseback rides, and just sightseeing in general are just a couple of the things to do in the park. Of course, just taking a day to go to all the different shops on main st. is always a good choice.