I live about an hour East of Bar Harbor.
Bar Harbor has improved a lot over the last few years. The Bar Harbor road (the single road in and out of town) flows much better now, many building restorations on the waterfront. Its really coming together. I'll try to think of some things other than small shops, Acadia National Park, and the waterfront that you may not find on the radar.
Food First:
* If you like movies, pizza, and beer, reel pizza smack in the middle of barharbor is a great little place.
Reel Pizza Cinerama - Bar Harbor, Maine, movie theater.
* There are places advertising Lobster EVERYWHERE, they are all delicious, any place you see along the Bar Harbor road is good
* A great place for breakfast, without tourist prices, would be just outside of barharbor, the Riverside Cafe is Ellsworth
Shopping:
* If you like antique hunting, there are many along the Bar Harbor road, but they are $$$. 30 minutes away, the best and most MASSIVE antique store ever.
Big Chicken Barn Books & Antiques
* If you like antique tools that are still meant for work, this place right in Bar Harbor cannot be beat
Jonesport Wood Co. Old Tools, Books, Antiques, Prints and more!
* One more antique place, which trumps the first antique tool place, but would be on your way to or from Bar Harbor is Liberty Tool
Welcome to Liberty Tool!
Sight Seeing: You'll find lots right in Bar Harbor, so here are a couple just outside I could think of.
* Not sure of your planned travel route, but if you happen to be driving US RT1, the The Penobscot Narrows Bridge in Bucksport has an observatory, its 450' high.
* If you are traveling the RT95 the Maine Forest and Logging Museum in Bradley is worth the time, Has a working water powered Mill. should you enjoy this type of thing.
Maine Forest & Logging Museum You should call in ahead of time to see whats up. This place is a hidden gem, depending on perspective.
If you want to see where lobsters and blueberries are really coming from, beyond the tourist towns, you'll have to keep heading East. But Bar Harbor is Beautiful, and you'll have a great time.