Before we get into the Rassmussen is a gold standard v. GOP Hack fun, its worth noting that his polling, along with Surveyusa, has always skewed heavily GOP in Maine. Up until the end, he had Woodcock either leading or tied with Baldacci in 2006, so LePage's numbers are basically identically to where Ras showed Woodcock at this point.
Isn't it possible that Woodcock was indeed ahead in ME but lost in the end because Moderates learned how conservative he was?
I think we give too much credit to general election voters knowing in June and even knowing what those who voted in the primary knew.