Hey there,
From what I remember being told, you'd have a better chance of staying in one place for all your rotations (not necessarily the same city, but the same area) if you had a family. It's easier to try to get places in closer proximity for your 3rd year rotations than for your 4th year ones. But then, this was told to me in October, so I might be missing some details. If you really want to know, you can contact the DMU people directly, or just wait and ask them at your interview.