Hi Golden Bear,
I live in Brunswick, and while it's crowded in the summer, it's not that touristy type of crowding you find in Camden or Bar Harbor. Instead, it's more like real Maine people being busy in real lives. :)
Brunswick has it's share of chain hotels, all located on major highways on the perimeter. I wouldn't recommend any of them if you want a real taste of town.
I'd say look at the cottage suites at the Middle Bay Farm B&B (a mile or two from the town center, but directly on the water) where you'll have privacy and lots of room but feel like you have your own place. http://www.middlebayfarm.com/ I'm not sure if they have bikes or kayaks there, but if they do it would be great as the inn has water access and that part of town has nice quite country lanes for biking. Or jogging, or after dinner walks.
And even though you sound not too interested in B&Bs, you simply can't beat the location of the Brunswick B&B. It's looks right out on the huge downtown grassy mall. Everyhting is within walking distance there. http://www.brunswickbnb.com/ There are community concerts at night, farmers markets during the day, a short walk to ice cream, movies, coffee shops, the downtown movie theatre, reasturants and bars, and if it's a pretty day, pick up picnic supplies nearby and eat lunch out on the grass. Or, buy hot dogs from the vendors who set up mobile food wagons during the summer.
I am a huge fan of the Grey Havens, but I think the cottage suites at the MBBB are a much better value; it will be quite expensive if you want a room with as much space and your own bath at GH. Plus, I don't think they have TVs at GH if that makes any difference to you.
Besides, if you go all the way out to Georgetown you will be fairly isolated. You could spend one day exploring Georgetown, Five Islands, Reid State Park, etc, but then you'll probably want to branch out, and it will be a whole lot more driving to make day trips to Portland, Freeport, etc. And, while I like Reid State Park which is right by Grey Havens, I prefer Popham Beach, which would be quite a haul from Grey Havens.
There are some fun restaurants in the Brunswick, but if you rent the cottage suite at the Middle Bay Farm you will have a kitchen of your own if you want to do a meal in/a fridge to keep your doggie bag fresh if you bring food home.
I second the recommendations of El Camino (don't let the exterior scare you away), Great Impasta (call ahead for reservations) and Back Street Bistro (get a reservation), I'll also add Wild Oats Bakery for breakfast, lunch and your sweet tooth. Great place to pick up sandwiches you can eat in or carry to the grassy mall for a picnic.
I also recommend exploring Harpswell, which shares a border with Brunswick. If you ride down to the end of Route 123 / Harpswell Neck Road, you'll see gorgeous New England architechture: lovely old grange halls, churches, salt water farmhouses. Then on the way back up 123, cut across Mountain Road to Route 24, then catch that down to Bailey's Island. It's lovely scenery.
Have a great trip.
I would recommend one night in Camden to break up your drive to Bar Harbor. Maybe 3 nights Brunswick /1 night Camden /3 Bar Harbor?