Its tough to fit in visits prior to R1 deadlines. You ideally will leave at least two weeks to work materials into your essays. So that would mean the first week of October would be the last point where it would be "worth" doing. I know GSB has their Live event, which is kind of like a day long tour event. They dont have class visits or anything arranged and there are going to be TONS of other people there so in my opinion its a toss up when to do it. Kellogg also didn't have scheduled visits available when GSB had their live event.
I would suggest staying near the loop, its kind of the mid point between the two schools and there are lots of places to stay and things to do. Plus its pretty easy to take trains to both schools from there. I have heard horrible things about trying to get from one school to the other.
Make sure you send me a PM when you schedule your trip. I am sure we can sneak you into some class for a visit, there are enough gmatclub members heading there that someone will have something interesting to go to.
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Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.