Jesus do I have to plan everything for you. Fuck.
Some Maine nerds here, but if they don't cover it, I will chime in. I'll assume you aren't headed inland to NH and VT?
Here are a few spots in Maine though:
Kennebunk/Kennebunkport: Find a parking spot near Federal Jacks. Get a few beers there. Then hit the Clam Shack at the bridge - get a pound of clam strips. Some people will say drive up Ocean Drive and see Bush's place. Don't. It's gay. You'll see lots of tourists and some "artists" painting nearby. Kennebunk beach (south of town) is really nice - especially after 5pm. If you are there around dinner time, Banaloop is a great place to eat. It's right in town. If you are looking for places to stay email me. The Colony is neat place to stay in town.
Portland: If you don't stop here and go to Gritty's for a beer and wings, be sure never to contact me again. One of the best restaurants is here - Fore Street. Maybe things have changed, but it's always been excellent. Tons of great food places in town. I've always stayed at the Eastland hotel when I visit. Nothing crazy fancy. Becky's Diner for breakfast. If you go to Demillo's to eat I will burn down your barn. Olive Cafe is a cool coffee spot right there on Commercial St. The bartenders at Gritty's are a good source of information as they are cool folks. Portland Head Light is a cool light house. But tons of great light houses to check out if that's your thing.
Freeport: Blow by town town unless you want to hit up the "outlets" and LL Bean store. A few cool places, but nothing as cool as Portland, etc.
Camden: Take a hike up Bald Mountain. Sea Dog Brewery is there in town. Lots of good places to eat and drink down around the river/falls/marina and on Main St/Route 1.
Deer Island is a somewhat of a pain, but if you want to do some sea kayaking there are TONS of great options and the paddling is super nice in this area. Lots of little islands to paddle to, etc. and some amazing scenery.
Countless little towns/areas all along the coast, but don't go all the way to Bar Harbor. It will be a shit show and I'm not a huge fan. I only went there to get the ferry to Nova Scotia. Acadia is really nice though, but not sure I'd want to drive all the way up to BH for it to be packed.
Boothbay/Boothbay Harbor is a nice area. Far more low key in this area, but still really nice/pretty.
July is a busy month on Route 1, so expect delays in the small towns. My favorite time is in September as the tourists die off and the temps are really ideal.
Email if you want more info as I have spent a ton of time on the Maine coast.
Even with the two kids you can hit up some cool joints. Most are family friendly, so really there are no excuses like " but I have kids".