Thanks again.... A little more searching, and I stumbled onto SAS charging about USD $400 for Stockholm-Newark RT nonstop (even though I was only going for a weekend). Even with a separate internal US RT ticket, it was a cheap option for where I was going (Bangor)....
I found it curious, in my searching, how few the air connections are across the border with little airports like Bangor. The only airport listed cross-border was St. John, NB, but as far as I could tell from their website PanAm (!) was not actually flying. So AC dropped out of the picture as a possibility.