I can only speak to the qualities of Greensburg (where Seton Hill is) and the surrounding areas. I went to Seton Hill for my undergrad, live in the Greensburg area now, and am from the area. There are some good school districts in the area. My kids go to Hempfield School District, which is a pretty good school. I am very satisfied so far with our elementary school, however, the high school graduates about 800 per class and covers a massive geographic region which encompasses very rural and dilapidated areas, middle class areas, and more affluent areas. Penn-Trafford, where I went, is one of the best schools in the state, and is 15 minutes from Seton Hill. As are Norwin, Latrobe, Greensburg Salem, and a private school, Greensburg Central Catholic. Latrobe is highly ranked as well. Its 20 minutes from campus, rural, small, has Latrobe Hospital, which is a small community hospital, and a highly ranked school district. Norwin is large and has more money. Its also 15 minutes from campus in the Pittsburgh direction. It's more expensive, but charming. I don't know much about GCC or Greensburg Salem other than that they are smaller.
It is very cheap to live here. Housing is affordable, rent or buying, and most places are safe. It's pretty open and some places are bucolic, which, depending on your taste, can be good or bad. The area directly around Seton Hill, downtown Greensburg, was once a charming place with small boutique shops and businesses, but is now dilapidated and has a sect of indigent and drug using population. That is the Greensburg Salem school district. Once you get out of the downtown area, which is quite small, it becomes much nicer and more suburban.
There are parks, some are nicer, some older, Pittsburgh is 40 minutes from Greensburg, the weather is temperamental and, for 4 months a year, very drab and sullen. Summers can vary from intolerably hot, humid, and sticky, to mild and breezy. Fall is beautiful. Spring, well, it's a complete toss up. There are a lot of younger families with kids, and a lot of old people. Not much in between. Overall, it's a typical, not very exciting, a lot of franchises, not much originality, and a lot of variance. However, it is not violent, or expensive.
As far as pre schools, there are seemingly millions. You need to differentiate, when choosing, between daycares and pre schools. My child went to one in Penn-Trafford, because a family friend owns it, but it is very affordable and nice. Also, you will most likely need to drive everywhere. It is not a walking or biking-friendly place.
I have only visited Erie, but they are pretty similar. Erie is colder. Both are affordable, have open areas, and a lot of demographic variance. Both have been affected by the recession, too. Greensburg, however, is closer to Pittsburgh; however, the main benefit of Pittsburgh for you as a medical student would be the access to UPMC rotations, which LECOM has severed. There is WPAHS, though, another large hospital system that still has rotations. And Seton Hill is a gorgeous, scenic, rolling campus, that is in the process of major growth. It can be annoying at time. When I began there, it was small, like 1,800 students small, and in the 5 years since I have began, they have added LECOM, several parking lots, ancillary buildings, all to support the arts, several large buildings in downtown Greensburg, again, all to support the arts, and now are beginning the construction on their new health sciences building on campus, which I believe will house LECOM.
Hope that helps. Any other questions, let me know.