Again and again, surfing the provincial Chinese-language media has turned up details that never make it up the ladder to Xinhua. The translations aren't always clear, but they get the basic message across. It takes some patience and willingness to experiment; using Google Chrome as your browser, set on automatic translation, makes it easier.
Some websites display images of the paper page by page, rather than translating headlines. Even then, you can find the articles (as I did with the Zhejiang post earlier today) by looking for "H7N9" in a mass of Chinese ideograms. When you do, click on the story and it will pop up.
The place to start is ABYZ News Links, and in particular the page China Newspapers - China Newspaper News Media Guide. This will give you a host of foreign, national and provincial links, listed alphabetically by the cities they serve. Scroll down and explore. A few provincial links will be dead, but most should give you something.
When a news item from Xinhua mentions a particular city or province, my instinct is to go there, or as close as possible. I don't expect to find a contradiction of the Xinhua story, but vivid and useful details often turn up.
Good luck. If you find any notably good sources, please let me know. And if you find a better way to surf these sites, so much the better.