I'm sure the previous links will give you the information you need, but let me tell you that we stayed at CSR for the Princess Half in Feb and it was so nice to be at the same resort with the Expo. They had sent out information on how you had to park at DTD and take shuttles and such, but we didn't because we were staying there. We checked in on Friday and got our packets and bibs that afternoon and the next morning the line to get in was several hundred people long, if not a thousand! Yes, the resort was busier than I've ever seen it (I've stayed at CSR three other times) but it was kind of fun to have the comraderie of so many other "princesses" staying there. The bus lines were pretty long on race morning, but I knew they'd get us there in time, and they did.
Having the Expo at CSR was sort of a last-minute change. It's normally held at Wide World of Sports but had to be moved for another event. It may move back to ESPN next year.
I believe all the Disney resorts were host resorts this year.