Blackwoods or Seawall Campgrounds- Acadia NP

We have stayed at both Seawall and Blackwoods, Hadley point campground, Mt Desert Narrows, and Bar Harbor campground. We prefer Bar Harbor campground. It is very well kept, clean, and a lot of their sites have more privacy than the other campgrounds. It is on the bus route, and it is the closest campground to the town of bar harbor. They do not take reservations, though, and take cash only. We stayed at blackwoods for a weekend last year, and ran our loud generator for a few hours. No complaints from anyone, although I did apologize to the closest neighbor when they returned from sightseeing and my genny was running. Seawall has lots of mosquitos. The island is really not that big, so you really cannot go wrong with any of the campgrounds.

Now that you're talking private campgrounds...a nice one in the Seawall area is Smuggler's Den: http://www.smugglersdencampground.com/

You can hike to the Echo Lake area right from the CG and the Island Shuttle stops at the CG office.

We were at Blackwoods in this past September, fully wooded pull through, nice hikes right from the CG, much closer to Bar Harbor, but not IN the town.
Generators aren't a problem, as long as you're not running it at night, we ran ours for an hour or so during the day.
Next time we may try Seawall. Acadia is an awesome place, and of course the food is part of that. ;)

I have been to both. Seawall has some first come first serve sites and is easier to get into in the middle of the week and is closer to the ocean. Backwoods is closer to Bar Barbour and all the tourist shops. Both are nice I but prefer Seawall.