Have lived in Maine all my life and driven Rt 1 between Portland and Bar Harbor more times than I can count, in all seasons of the year. Would agree with Bonniemaev that it's not as scenic as most people expect... but it truly does depend on ones expectations. Most people hear the term "coastal Rt 1" and expect it's going to be like parts of Highway 1 in California, with mile after mile of uninterrupted views of the ocean and coastline. But a closer look at a map of Maine will quickly dispell that idea. It's called "coatal Rt 1" because if parallels the coast, but isn't necessarily "on" the coast.
If you can picture the coast of Maine as being like the palm of your hand, with your palm representing mainland Maine and your fingers representing some of the dozens of peninsulas along the Maine coast (and the space between your fingers representing the Atlantic Ocean), US Rt 1 follows the row of knuckles closest to your wrist... meaning you'll catch occasional glimpses of the Atlantic between peninsulas, but to get the classic Maine coastal views folks see on postcards and calendars, you really need to take the time to drive down the peninsulas to the small coastal towns...but then to proceed further down the coast, you have to drive back up to Rt 1 again to resume your longer trip....
And as Bonniemaev points out, although its only about 160 miles via Rt 1, it can take four hours or so in the summertime, because, while it serves as a major through-route between those two places, it also serves as the Main Street of numerous small Maine towns, the access route for local commercial traffic serving those towns, and a major route for local-folks headed out to do their day-to-day errands. Speed limits through those downtowns drop as low as 25-mph and, in some towns, roadside parallel parking and numerous side streets add to slower going. If folks are truly in a hurry to get from Portland to Acadia to maximize their time there or from Acadia back to Portland as quickly as possible, most of us recommend using I-95 (or a combination of I-295 and I-95) from Portland to Bangor, then I-395 to Brewer, US Rt 1A to Ellsworth and Rt 3 to Bar Harbor -- it is longer, but often considerably quicker because much of it is limited-access, divided multi-lane Interstate highway. Just something to consider as you plan your trip.
Jonesport and Cutler are both small Maine coastal towns in eastern Maine -- Cutler has a nice harbor and about 500 year-round residents. Jonesport is home to about 1,500 people. Doing a Google search for each town and finding their official town websites will also give you a photographic look at both areas. Whether or not photos like those on the websites are worth the extra driving or not is a decision only you can make. The only thing I can add is that visiting that area of our state will give you a totally different view of Maine than what you'll see in Bar Harbor or points south of there along the coast.