If you think you might need an Affidavit of Single Status during your visit, then you may need to get one stateside or plan on going to another embassy to get the Affidavit. I found this while doing some research, thought I would give you the heads up!
The U.S. Consulate General in Guangzhou will soon move to a new and spacious facility in the Zhujiang New Town neighborhood. During our move it will be necessary to suspend temporarily our usual passport, extra pages, consular report of birth, and notary services. From July 15 through July 22, appointments and passport pick up will not be available.
We encourage U.S. citizens in south China to check family members’ passports and to schedule appointments now if necessary in order to avoid inconvenience or disruption to summer travel plans.
Appointments for passport and notary services may be scheduled on line at https://evisaforms.state.gov/acs/default.asp?postcode=GUZ&appcode=1 (https://evisaforms.state.gov/acs/default.asp?postcode=GUZ&appcode=1).
Here is the consulate link that has the notice. http://guangzhou.usembassy-china.org.cn/service.html (http://guangzhou.usembassy-china.org.cn/service.html)
Good Luck and Best Wishes, Robertt
P.S. If you get one state-side, you need to verify that it will be accepted at her local marriage registration office. You can download a blank copy of the Affidavit and e-mail it to her to take to the registration office for their decision. I used this company in New Jersey to get mine back in 2009 and it was accepted without any problems, you can ask the company rep. to be certain though. They know which provinces accept their documents. Here is the link for the Affidavit of Single Status. http://www.visarite.com/SingleStatusAffidavit.htm#.UcIwh7Q4Kx0 (http://www.visarite.com/SingleStatusAffidavit.htm#.UcIwh7Q4Kx0)