I lived just outside of Mifflintown for 10 years (1989 - 2000) and we stayed only as long as my husband could telecommute. For a few months before we moved to the Harrisburg area, he commuted to a new job east of Harrisburg (towards the Hershey area) and that wasn't something we were willing to live with.
If you are students, why not get two smaller apartments, one in Hershey and one in State College, and take turns commuting on weekends. There's nothing to do in Juniata County, unless you are thinking of moving there to be near the Port Royal race track?
One big issue (for me, anyway) was the lack of fast internet connection. A lot of the phone lines are very old, and several of the townships never allowed a cable company in...er, the cable company wouldn't pay the required bribe and who can blame them?
From what I remember reading in the local weekly paper (a folksy fishwrapper with no pretentions of journalism) rentals were pretty cheap, but you get what you pay for.
I really don't know what to say about Mifflintown other than:
DON'T DO IT!
Never lived in Perry County, but met some very friendly people in Newport. The town itself has an interest in revitalization, and has some cute shops -- is very walkable, too. Would say crime in Newport is much, much lower than Mifflintown. The state police are right outside the town, so that helps keep the gang and drug activity down.