There are 2 Buck's Harbors in downeast Maine, one big one near Cutler and one in Brooksville. I assume you mean Brooksville. vbm is correct, but depending on your needs and arrival transport from NM, either Tradwinds in Blue hill or Shaw'sm or Hanneford Supermarkets in Ellsworth may fit the bill.
I was about to email you about some Albuquerque info. and I stumbled upon this thread, as I'm moving back to NM the first week in August, I work as a registered Maine sea kayak guide, often out of Stonington. Please email me and I will give you my phone number. I know the coast well and can give you a wealth of information. I hope you can do the same for me when I return to NM after 30 years. I remember no houses on 9 mile hill west of
Bucks Harbor Market , a short walk from the marina is an excellent small general store. Good for cheese, bread, local vegetables, and basics. Often it will have some limited selection of good meat or fish. It has a good wine selection. The marina has had lobsters in the past and one can often buy them from passing lobstermen while cruising.
On Tuesdays there is a local farmers market adjacent to the general store. There are also farmers markets in Castine on Thursday, Blue Hill on Saturday and Wednesday, and Stonington on Friday.