When we went on China & the Yangtze in 2007, we used almost exclusively Chinese currentcy, although street vendors will accept US dollars. Almost everything hat the sell will be one dollah ot 2 dollahs. We did not end up buying a single meal that was not includined, so we did not need any money there. Anyone that you will be tipping will accept US. If you go into a small store or take a taxi, however, they will generally want Chinese currency. It is readily available at ATMs and the hotels will generally break the larger ATM bills to smaller denominations.
One couple on our trip upgraded their cabin on boarding, and liked it, but our cabin was comfortable and all of our cabins were clustered together right near the small library, so we had a meeting place, mostly to ourselves. The ship was a sister ship to the one used by GCT in Russia, before they got their own ships, but the chinese version was better apponted and more comfortable,
For our trip report on the trip see http://jackthetravelingman-china.blogspot.com