Hi Clair de Lune;
I moved for my internship and will be moving again for the rest of residency (I'm doing prelim medicine). I moved alone and didn't know a soul in the new city but moved for a good prelim program.
I am actually very family oriented which is somewhat of a strain b/c you miss family a lot. But if you make friends fast you shouldn't have a problem. Residency tends to bring people together b/c you are all strained and going through the same thing.
One good thing about a new city away from all those you know is reduced social responsibilities. If I was close to home I would be expected to attend various social functions and, with internship schedule, you often cannot. If you go away for residency, enjoy it. Think of it as your chance to learn how to be more independent and adventurous. Discovering all the aspects of my new city on those precious days off is really fun and gives you a sense of accomplishment.
However, make sure you choose a program with weekends off that are frequent enough for you to fly home and see your loved ones (electives and clinics are usually when you have free weekends). And always ask about sick call. Although some programs claim endless free weekends during appropriate rotations, sometimes you are on sick call (backup for any sick resident) on those weekends so be careful.
Be adventurous and don't be afraid to move to a brand new place.