I would say most schools are what you make of it. If you want to behave like a 21 year old undergrad, there will be classmates with the same mentality. However, if you have 3 kids and are more interested in play dates then there will be some people who want that too. The larger the school the more people with like personalities, and the closer to a major city the more there is to do. Everyone living within close proximity helps.
Each school offers a little something different. Having spent two years at Kellogg, I can assure you no matter what your personality and lifestyle you will find a group of friends. If you have kids and/or family some schools definitely offer more for you in that regards and suggest you research that.
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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.