It depends on what kind of residency programs you plan on applying to. If you are leaning towards fellowship/academic pathways I would suggest an away at one of those programs, but if you want more community practice do an away with them. If you have a particular favorite program in mind, try to go there so they can get to know you, but remember it's basically a month-long interview.
I can't comment on the community programs, but for the academics, several people on the interview trail this year did an away at UNC and loved it. Duke and UAB were also popular destinations, so you wouldn't go wrong with those.