We were there from Oct 11-15 (Mon-Fri). What we found was:
Monday (Oct 11) - Animal Kingdom - It drizzled much of the morning and this seemed to keep the crowd down. In the afternoon it POURED for at least a half hour. This probably sent folks home early. All in all, the park wasn't that crowded. With fast passes we did Kilm Saf twice, Prim Whirl twice, and everything else once.
Tuesday (Oct 12) - Disney Quest - We started for Epcot but it was already drizzeling pretty good, so we decided to switch up days and go to DQ. It actually stopped raining shortly and turned out to be a nice day. DQ wasn't too crowded. We did the Pirate simulator 4 times (best darn thing there by far).
Wed (Oct 13) - Epcot - Sunny, and a little cooler. The park was a good bit more crowded. We did most everything (Test Track twice) but by the afternoon the crowds were tough at the big rides. We tried to go back to Test Track at 3pm. The line was all the way out the door and fast passes were giving 5:20pm as the return time.
Thursday (Oct 14) - Magic Kingdom - Another nice, cooler day. This was EE day, and things did seem a little crowded. But, with fast passes we did everything (included Splash M twice) without bad waits (nothing more than 10 minutes).
Friday (Oct 15) - MGM - Alot cooler day, but sunny. It POURED down rain about 10am, but quit after about 20 min. The park was a little crowded but manageable. With Fast Passes we didn't wait long for anything (< 10 min). I believe we did everything but RRC.
In short, if you use the fast passes, you can easily do everything once and several things twice. Go early (early entry), knock out a few rides in the first hour, and always get your fast passes (get one during EE for something later). Do the popular rides early, save the not-so-popular rides for later. Get fast passes for things you want to do a second time while you are doing the not-so-popular things. Also, check the wait times. Long lines don't necessarily mean long waits. Most wait times are also overestimated. Hope this helps.