Downtown will be a mess. The fourth weekend in October seems to be the spot that F1 has settled on for the USGP. If Texas can arrange things to have all Thanksgiving games in Austin, surely they can get an away game on the fourth Saturday in October.
F1 Qualifying is 1 until 2 with activities at the track before and after. Morning (except around the Convention Center parking) and afternoon should be ok. Friday and Saturday nights will be interesting.
I have to say, I'm with Worster on the start time. I've ALWAYS hated 11 am kicks, even a thousand years ago in college, and even if I was a good boy the night before. Football just seems more natural and appropriate in the afternoon and evening. (Having written that, I did quite enjoy the game this past Saturday, but that was DESPITE the 11 am kickoff...)