However, it is possible to have 'article too long' errors due to lots of posts. Info here: http://support.google.com/news/publisher/bin/answer.py?hl=en&answer=93994

Do you use a Google news-sitemap? If so, any errors like that will show up on webmaster tools and then you can address them. If you are not getting errors, you are probably ok on this.

I don't see any particular plugins for breaking posts over into another page. That's surprising. I'm short of time at the moment, but will look again when I have more time if no one else chips in here with one.