re-visiting schools post acceptance

i am having a really hard time deciding. i will probably visit the schools and hopefully be able to make a decision based on the visits. prior to the visits, does one generally call the office of admissions or just kinda show up? i just want to get a better sense of what the schools are actually like when they are not trying to "sell" it. also, is it completely out of the ordinary to call the office of admissions and ask them questions i dont remember them answering during the tour? for instance, i know that columbia is changing the curriculum next year and i am interested in hearing more details and how that will effect pre-clinic etc...
thanks for any suggestions.