I’ll start, in Wellfleet MA there’s a place called Ceraldi that uses ingredients sourced from around Cape Cod to create a multi-course meal that is a really unique experience. Their menu is apparently changing with the season based upon what ingredients are available. They also serve local drinks with each course. When I went a few years ago it was pricey at $100 per person, but we got 7 courses and left full and tipsy. I personally enjoyed it enough to recommend a visit if you find yourself in the Cape Cod area.
Ogunquit, ME is really lovely in the summer. But better to go early or late in the season to avoid crowds.
I’ve been there! I went during the summer, but it wasn’t great weather at the time. Despite that, I still really enjoyed hitting Main St.