Post w Shanghai Greeters: Volunteer tour guides in Shanghai

I bought a ticket to Shanghai (from the US) but found that I need a one of the documents below. Has anyone been to China and do you have experience with this? I do not want to go on a tour and I don't have family there. Letter of Invitation- China (Los Angeles) One of the following documents must now be submitted when applying for a Chinese tourist visa: An Invitation Letter from a Tourist Group or an Invitation Letter for Tourist (China) issued by a Duly Authorized Tourism Unit or; An Invitation Letter from a family member. The letter must be specifically written (sample: Invitation Letter from Relative). You must include a copy of the passport data page and Chinese Residence Permit (if not Chinese citizen) OR copy of Chinese National ID (if Chinese citizen) of your host.