Local press has always been a bit less examined than DC press, but it is just as pernicious. With very little information in most electoral environments, local endorsements are useful as props in campaign commercials, as in 'Dave Reichert has been endorsed by XYZ papers'. I don't know if this affects voters, but it certainly affects politicians when they consider voting against the agenda of these newspapers, which often amounts to a pro-choice neoliberal ideology.
Another interesting element of local press endorsements is that they are often really really stupid. For instance, the Democrat and Chronicle in upstate New York actually attacked Democrat Eric Massa for knowing a lot about policy: "Massa is a walking briefing book when it comes to the issues. But his connection to constituents is less clear, less developed. He's a big-picture guy in a district with small-picture needs."
As an excuse for endorsing Kuhl, who pulled a couple of shotguns on his ex-wife, this paper argues he's 'grown in office'. That's the same reason, the same wording in fact, as the PI's endorsement of Reichert (he's 'grown' in office as well).
Mostly campaigns come down to huge amounts of paid media, and newspaper endorsements are playing less and less of a role. These papers also tend to hate liberals; the Tacoma News-Tribune cited as a criticism of Darcy that "she is a celebrity in the world of MoveOn.org, ActBlue and the Daily Kos. Her campaign has been powered by vast sums of money from the liberal blogosphere."
It's all very stupid and corrupt. These papers are not performing a public service, they are pushing a specific agenda, and they don't like people that trod on their hallowed trusted turf.