Internet in China is very easy to get at most any shop, even if you dont know the APN settings and the like, just look on google the resources are plentiful.

I spent just 100RMB on my SIM card, all phone calling, SMS and data services for 2.5 weeks in china, and it was very easy, I went with China Unicom 3g GSM services (they have CDMA as well), a few times it fell back to 2g EDGE but continued to work, for emails and the like.
I got almost daily updates of the amount of credit left available and left the country with 30+ RMB still left on the account and some data allocation as well.

The main VPN issue will be with 2g networks EDGE speeds you'll be too slow to link to vpn sometimes, but overall even without vpn there you can get by most of the time.

The other thing is to be sure you have DNS servers set to not pickup from them or you will have poisoned DNS on your phone and even if on a vpn it won't work for accessing a few sites.

I rather liked some of the ads not working and youtube embedded broken when on a slow edge link while on a train

Also watch out for SSL sites not working in a few areas, DONT fall for the temptation to login to non ssl if offered, just wait!