Concerning Maine:
Bangor (1-1 1/2 hours from Acadia) Has a shul w/daily/ shabbos minyanim-www.jewishbangor.org. The 2 hotels listed on their site are within 15- 20 min walking distance. I stayed at the riverside inn for shabbos( part of a medical center)because it has a mini suite (no kitchen) and no uphill walk. If I would go back I would try to rent the shul kitchen to eat there. They used to sell some frozen stuff (empire chicken etc..) in a local kosher resturant, but that place is no longer kosher.
Acadia: The above website has link to a Bed and Breakfast (vegetarian?)in Acadia, but I don’t know enough about it.
Portland has a shul that advertises themselves as Orthodox, but I would check with a rav before davening there. There is Chabad there for about 30 years that might have a minyan on Shabbos.
If you go north above Acadia the crowds thin out dramatically (As do the accommodations). The drive is scenic. Campabello Island (about 2-2 1/2 north of Acadia) is a great visit. It’s Canadian territory, but they let us in on expired passports (the border control is easygoing- call them). There’s no wait at the border. If you want to splurge a little, the Whale watching (August is better then July)is great. Acadia also has Whale Watching, but there are differences. I have more info on that if needed. The Roosevelt Estate is relaxing and free. I’m thinking about returning to that area in August if I can find a decent house to rent.