AK gasoline, basis Anchorage, typically has had (historically) a 10-17 cent transportation premium. This changed in the early days of the pipeline, but began reverting to historical levels, oh, 15-odd years ago. I suspect (but don't know) that the pipe is now more-or-less unidirectional, which would account for this occurrence.
The gasoline I buy is trucked from Anch to Fairbanks. It is slightly more expensive than local refinery gasoline, but only because it is a full service station rather than a gasoline island at the dept store or 7-Eleven.