Since they are not that far from EWR I would assume that's their starting point. I originally thought that maybe the prices were high because it was a bit early for booking but when I went back month after month it seemed to be consistently high.

I did compare the my same dates in January that are $457 from BOS against leaving from EWR and United has a $534 R/T N/S both ways...so maybe it's the dates/season that
is the issue