Almost no one moves every few weeks during 3rd and 4th year, and those who do usually chose to do so (a select number of people utilize free housing at off-site rotations for most of the year and sublet the rest, essentially living without rent and saving tons of money - but this is not for everybody). The Vast majority have a "home base" in westchester or the city, where they have a yearly lease on an apt, and stay there for most of the year. So far as I can tell, it makes no difference where you rotate when it comes to residency selection (programs will probably never know or care where you did a clerkship, they look at your performance). Every year, city based people and westchester based people match into great programs. When the time comes, where your "home base" is becomes simply a matter of preference. My base is the city. Another poster here is based in the WC. He/she has easier access to class meetings and student affairs. I have easier access to Thai food. Neither has a residency advantage....if you are married, you can/will fill out an exemption form during the lottery and will essentially get your location of choice (as long as there is a good reason, ie my spouse lives/works in NYC, or my kids go to school in Valhalla. No worries.)
Random Info: Match data from the Dean's office said that we had 98% of students match, and everyone who scrambled had a spot by match day....Financial aid filing for current students has begun, so you will be hearing about it in awhile. Those "avg debt" numbers seem low to me (since I'm one of those fools who will be in the 240,000+ range), but there are many people who do not take out the full amount of loans for various reasons. Some people have parents and other family funds (I suspect there are a number of folks in my class who have parent's footing the bill. Lucky people, to say the least), a few have scholarships, etc...The average is likely brought down by this....