Oh, and I screwed up and forgot to book my room until 3 weeks ago. Got the DLH for $399 a night.
Not exactly in my price range since I like to pay that for about 3 nights. That's pricey for me. And now they're all completely booked per
disneyland.com.
Also, Courtyard Marriott Water Park is over $400/night. Hilton - $900/night. Hyatt Place - $400/night.
But I just looked up hotel prices on Orbitz for the
week of Thankgiving, Monday before to the Monday after, and you can find Hyatt Place at $208, CMWP at $278, and availability at HoJo, Desert Palms, Castle Inn, and Grand Legacy. A major holiday like Thanksgiving, and there are still rooms (some at decent prices) just two months out. But the race weekend has nearby Harbor and Disney hotels nearly booked solid.
It just seems to me, from these numbers, that the races affect DL far more than most realize. And I can personally vouch for that, going before or after that weekend the last 4 years. The crowds and hotel sell-outs have gone up wildly the last two years. When approaching the OP's question, the answer is definitely in the Disney races.
As for how that will affect crowds (to the OP), Monday will be pretty busy (especially at security) as racers will hang around for a day or two to enjoy the parks. By Wednesday, it'll start to clear up. If you were to book a hotel starting on Nov 13th, you'll see hotel prices take a nosedive. Not sure if you can move the date one day, but it might be worth it.