One of the first things I checked was the media market in Maine. The two largest papers are The Bangor Daily News and the Portland Papers, or the Portland Press Herald and Maine Sunday Telegram.
The Telegram and Herald have an interesting politics page, which even features a Politifact-style section called Truth Test. Its format will be familiar to readers of Politifact, complete with the images of gauges that convey the degree of honesty in the claim.
At the time I looked, Truth Test featured a fact-check of an ad by the campaign of Angus King, an independent. Despite not being one of the nationally known fact-checkers, I found the article well done. It was detailed and summarized the evidence well.
Major TV news stations include WABI, Bangor's CBS affiliate. A second is Portland's WMTW, an ABC station. This is their article about Angus King's foray into TV. Compare that to a similar story their rival WGME. Initially, I'm most impressed by WGME because their coverage seems the best and most detailed.
King was Maine's governor until 2003. He ran for both gubernatorial terms as an independent. He's generally taken Democrat-friendly stances and he's expected to join the Democrats' caucus. Officially, he's refused to say either way.
Charles Summers is the Republican nominee. He is currently the Secretary of State for Maine. Cynthia Dill is the Democratic nominee. She is currently a state senator. Her prospects are dimmest, as she's polling under 10 percent. The Washington Post published a profile of King's opponents in June.
King is leading by a 30 points, as Nate Silver recounts in this look at senate races, as he has been since June.