I agree with what's been said -- although, FWIW, I worked at a major city newspaper for a number of years, the bulk of the time in the editorial office, and sometimes columnists just went off the cuff with something that struck them -- and our editor let them (say, a week or less to deadline). If it's a true human interest story that a columnist would really give life to -- the'll go there, even a couple of days before deadline. If just a listing of events (yes, I did that too), definitely a couple of weeks out to a specific date.
And, again, not sure how this works for local papers, but in our newsroom, you could send the same press release to three different departments initially, and it would all wash out, as far as who would cover it and how.
(And, now with online news, I work for events listings of a big-city website and I often post things on the day that they happen....)
I guess what I'm saying is -- sooner is better. But the story might get picked up just a few days before the event, depending on the news cycle and available inches.
