I was born and raised there in Beaver Co until about 19, then moved down to Tampa Bay where I still am today, but am seriously considering going back. There are alot of very affordable homes all around and so much beautiful countryside! The town of Beaver is an awesome place to live and raise kids. (at least it was when I was growing up there) The population is about 5000. It's very quaint and a place that is family friendly with very very low crime and the kind of place where generations have lived there and gone to the same school (some teachers have had several generations in their class...mother, father, their children, and then grandkids...).
The town and the whole area is very rich with history. Many of the roads are old Indian trails. There are grand old homes along the river that where part of the "underground railroad" that have hidden tunnels and fake walls... There are Indian burial grounds and the old Ft. McIntosh ruins down on the river bank also. Just alot of really neat things like that. I read recently that the historical society was thinking about putting Beaver on the registry of historical places or something like that.
I would avoid some areas such as downtown Beaver Falls (lots of crime) and the towns near the Shippingport nuclear plant (a little west along the river), Midland, Industry and anywhere close to it.
Nearby, McConnells Mill is an awesome natural park with creeks and forest... lots of folks get married along the trails and streams there.
There are old covered bridges around the area and not too far is Amish country. They are facinating wonderful people that can make you the most fine leather for your horses. Lots of woods and streams and lakes around. This is a place where you can pack a picnic lunch and drive out in the country and just park along the road and go take an afternoon walk in the woods. Also wild berries to pick in many places.
When I lived there, holidays were special. Everyone decorated TOTALLY all out for Christmas and there were door to door carolers. The city held a parade and Santa threw candy for all the kids. Haloween trick or treating included any house in town with a light on. Down home Americana.
There are lots of homes with land if thats your thing. So it's easy to have a quiet country feeling and still be near town. The homes in town very typically are older "grand" type with big rooms and lovely woodwork. They often have 2 stories, an attic and basement (often finished living spaces) giving you 4 stories of house and fireplaces on 2 floors! And Pittsburgh is only 35 or 40 minutes away, so alot of folks commute.
There is alot of snow during the winter, but the fall follage is so spectacular. Unfortunately there are not endless days of sunshine like we have in Florida, it is rather gray and overcast for long periods with all-day rain sometimes, so that may be something that bothers you (some do, some don't).
Oh! and you can actually lay in the grass without the fear of fireants! And the bugs are just nothing like here in Florida lol
I know there are many other towns around there that are nice as well, I just know how partial I am to my hometown as I think it has a certain charm that is a bit more "homey" than some of the surrounding towns. But there are lots of wonderful areas around to live.
Sorry so long! Hope that helps you some

Good luck and keep us posted. Any questions, fire away!