Interesting thought but even I think going to 64 is too far, especially considering that D1A has just 128 or so teams. I've always been an advocate of eliminating CCGs and going to a 32 team tournament, with all 10 D1A conference champs guaranteed a bid. The rest would be at large. So that would entail 5 weekends but they needn't be consecutive. The tournament could begin during the first week of December, when the CCGs are currently held. Then they could skip a couple of weeks for finals to the weekend just prior to the Christmas holiday, when 16 teams would be involved. The 8 winners would play during the NY weekend. The 4 survivors would play a week later in early January with the NC game a bit later in January, right around the beginning of the "spring" semester or winter quarter for most schools.
Realistically, that kind of schedule would involve the least disruption to academics, provide all conferences with a shot at the NC, and lead to more variety in the schools getting to the tournament over the years. Limiting things to 4 or even 8 schools will soon likely result in a lot of repeats year after year.
Also, I don't favor using home stadiums for the tournament. There are several great venues that would work in the Northeast and Midwest, with several domed stadiums (Indianapolis, Minneapolis?, St. Louis, Detroit, Chicago?) in the latter and usually not too cold temps in the former, where the Meadowlands and the Linc could come into play. Then the higher seeds would get to play in a venue closer to them to anchor ticket sales, but not in their home stadiums.