You can’t go wrong almost anywhere along the ocean in Maine. Camden, Boothday Harbor, Rockland and Bar Harbor are all fabulous mid-coast towns. Portland is a small but very nice city. i’ve ehar Oganquit is nice but haven’t stayed there myself. All of them have good seafood restaurants and great boat excursions ans scenery. There are great B&B’s in each of them. Early June will be before the “main” tourist season so it should be a little less crowded. Might be chilly at night but then Maine often is and that’s part of what’s nice about it. Just check and make sure it’s not black fly season; I’m not exactly sure if Maine has one but I think they do. As you can see, I am a Maine enthusiast. We go up to Acadia every year – if you like hiking, that’s a great place to go.