I am a US citizen with a multiple entry business visa valid until Nov. 11. I am flying to Beijing on Oct 18 and returning to the US (from Shanghai) on Oct.
31. Two questions.

1. I am pretty sure this visa is valid for the trip since my entry is well before Nov. 11. Is this correct?

2. I've never had a multiple entry visa before. Do I need any documention for my trip (eg hotel bookings, invitation) like I did to get the visa in the first place for my June trip? Will I have to produce this at the airport in PEK to get in the country or will just the valid passport and visa suffice?

Thanks
David