Detroit, Road America, and Homestead are the ones that have the biggest question marks on them. If my wife is working, it will be part time, and I started with 3 weeks of vacation so time isn't going to be all that much of an issue, just the transportation and overnight costs for each.
Lime Rock, NJMP, Mid Ohio, Watkins Glen x2 and Indy are the 6 easy ones. Indy is the farthest of those, but no way I'm going to miss that race.