I lived in Bar Harbor for 3 years when I was at The Jackson Lab and we also vacationed there many times. Here is some info I had sent to a friend of mine about a year ago that was heading up there. As an addendum to the lobster pounds don't miss Thurston's Lobster Pound in Bass Harbor.....fully enclosed screened seating on the water - great food in addition to lobster, nice bar, etc. The only caveat is waiting to place your order...use the mosquito repellent by the door.
Hotels
Most of these are in town Bar Harbor or just outside of town on Route 3 (Eden Street). All are pretty well rated but the first one is one we stayed in and is reasonable as far as price and pretty nice, clean, etc. As far as B&B's....a former co-worker of Steve and mine from Celgene owns the Holbrook House on Mt. Desert Street (Michelle is her name)...their place is nice and is pretty reasonable too but you would likely need 2 rooms there.
http://www.barharborgrand.com/ (we stayed here a few years back and it's reasonably priced and in town)
http://www.theharborsidehotel.com/
http://www.atlanticeyrielodge.com/
http://www.barharborinn.com/
http://barharborhotel.com/
http://www.theweststreethotel.com/
Restaurants/Pubs
The Thirsty Whale on Cottage St - this is a pub that also serves very good lunches (fish sandwiches/lobster rolls are particularly good) and has a good selection of the local beers. Very informal - music on weekends.
Geddy's - pub on Main St. - also very informal and great burgers
Galyn's - next to Geddy's on Main St. - more formal and pricier restaurant (but not too pricey) specializing in seafood. They are really quite good and when I worked at the Jackson Lab we used to bring a lot of visiting scientists here.
West Street Cafe - on West Street - very casual sit down restuarant that has good seafood at reasonable prices - very kid friendly.
Cafe this Way - down a small dead end street off of Mt. Desert Street - probably the best breakfast in town (my favorite anyway) - great omlettes, eclectic setting with bookshelfs all around - for breakfast need to get there early or there will be a wait, but it's worth it. Can't go wrong with the breakfast burrito - they also serve dinner here which from what I have been told is also very good.
Jordan's - on Main St - a "diner-like" place serving breakfast and lunch - also usually a wait for breakfast but not as bad - decent food - specialty is blueberry pancakes.
Two Cat's - on Main St - part of a B&B now but also a good breakfast place open to everyone.
Side Street Cafe - on Rodick St. - American fare that's quite good with really great drinks too
Havana - Cuban restaurant on Main St - I haven't eaten here but have heard good things about it.
Guiness and Porcelli's - Italian restaurant on Main St. - newer place - we ate dinner here last year and it was very good - a little pricier but good food.
Jack Russell - on Route 3 as you come into town. Good steakhouse with good beer - home of one of the 2 microbreweries on MDi (I'll get to that in a bit).
Rosalie's - on Main St. - Pizza place that probably has the best pizza in Maine - this is the closest approximation to good NY/NJ pizza and it's pretty good. Usually quite a crowd.
Morning Glory Bakery - Rodick St. - excellent breads and pastries/pies, etc. Coffee rolls are particularly good as are the various scones and bagels with spicy cilantro cream cheese.
Jordan Pond House - along the Park Loop Road in Mt. Desert (NE Harbor) - somewhat pricey for dinner not as much so for lunch but great food. Known for their popovers - you can actually go there in the afternoon for tea and popovers as well as lunch/dinner - usually a wait but they move things along. Can drive in or even take your bike if you happen to be biking on the carriage roads in Acadia.
Beal's lobster pound - on the waterfront in SW Harbor - if you don't feel like cooking your own lobster this is a good and reasonable priced place - great view on the working waterfront. Trenton Bridge Lobster Pound at the head of the island as you come onto MDI is also very good (great chowdah!)
Trenton Bridge Lobster Pound at the head of the island in Trenton, ME - killer lobster bisque and hard shell lobsters
There are a number of other restaurants some pretty expensive (Rose Garden at the Bar Harbor Hotel, Reading Room at the Bar Harbor Inn, George's) which all are rated very good but I haven't eaten at any of them.
If you like beer there are 3 microbreweries: Bar Harbor Brewing (which has tours/tastings at their new location on Mt. Desert Street), Atlantic Brewing (also had tours/tastings - they are off of Route 3 in the village of Town Hill) (BH and Atlantic Brewing have merged) and Maine Coast Brewing (based out of Jack Russell's).
Bar Harbor Brewing: Cadillac Mountain Stout and Thunder Hole Ale are my favorites from them but they have a few others too.
Atlantic Brewing: Bar Harbor Real Ale and Coal Porter are my favorites (Coal Porter is pretty potent) - they also have other selections as well.
Maine Coast: I'm not as familiar with their beers but they do have some nice selections
Outdoor Stuff
South Face Trail up Cadillac Mountain - it's a nice hike (about 4.5 miles one way) but not too strenuous as the climb is gradual. Other trails that I like are the Gorge Trail (goes up between Cadillac and Dorr Mts and crosses a stream at a number of places as you go up), Champlain Mt. trail, Seargant and Parkman Mt trails, Great Head (along the water near Sand Beach and not too bad), and the Beehive (a ladder train that it a bit strenuous but fun) - you can then descent from the Beehive down the bowl trail. Also Norumbega Mt., Parkman, Sargeant Mts on the West side of the island are some good ones.
You can also canoe (rentals available in Long Pond at Pond's end - National Park canoe rentals), there are a number of sea kayaking tours which are a lot of fun (Western Bay on the other side of the island is a little quieter with boat traffic than Frenchmen's Bay), as well as biking on the carriage roads. We did the kayak tour on Frenchman's Bay from the place right on the waterfront in town which was pretty cool. Also went rock climbing last year with Acadia Climbing School.
