The Vegas books will continue to take bets, but the bets at those 5 tracks will not be included in the parimutual pools. And of course the races won't be shown. It's not clear from the article I read (below) whether live odds will be shown.
There will probably be some kind of limit on getting full track odds. The guy at Jerry's Nugget said they would only cover $200 at full track odds; anything above $200 would be paid with a cap of 20-1 for win, 8-1 for place, and 4-1 for show. I'm guessing Caesars or the Hilton would have higher limits than Jerry's.
http://www.gamingtoday.com/today/story.bv?storyid=19905
--Dunbar