There were no Brewster's in Maine to my knowledge. I grew up in Bangor in the 60s, and spent time in Bar Harbor and Ellsworth in the summer(Hancock County). The chains that we had in those days were Zayre's, S. S. Kresge's (Later K Mart), Mammoth Mart, W T Grant, and A & P food stores. They all had a local feel about them, and we also had a 5 story local store called Freese's, which was in business from the late 1800's until the 1980's. There was no Bangor Pine Hotel, as in early DS, but there was a Pine Tree Restaurant that was quite famous locally. Other regional/local food chains included the Shop n Save Chain (now Hannaford Brother's), which was usually locally owned. This meant that each Shop n Save also had some guys name on it, like Don's or Doug's.
We Had IGA foodliners, my grandmother's favorite (double coupons), and mom and pop stores could choose from suppliers like AG(Associated Grocers) or Surefine. These mom and pop places were where you were most likely to pick up the Dark Shadows bubblegum cards and posters. Below are views of the old Broadway Shopping Center, where Zayre's and Kresge's were, and just for fun, here's a view of Downtown Bangor from the late 1800s -early 1900s. You can see the Penobscot river in the background. This might have been how Edward or Barnabas might have seen it, eh?
Petofi