The only thing that makes traveling the country of 1.3 billion more difficult is when the 1.3 billion are also on vacation. The eastern region of China is heavily populated, and during the three weeklong public holiday periods, it seems like everyone takes to the road (or train, or plane).
Hotels in major destinations are booked solid and even the quietest of destinations become packed with fellow travelers. Try to avoid traveling during the Chinese New Year, which is based on the lunar calendar and changes date every year. The National Week holiday in October, and the International Labor Day holiday in May, can be easily avoided with a bit of planning.
Another bit of advice: buy a good map. Cities change quickly so it's worth making sure you have an up-to-date map to help you navigate.