Greensburg is about 45 minutes to an hour (average) from Pittsburgh. But it depends on where in the city you will be working...because of bridges and tunnels you have to cross, which add time at rush hour!!
Good places to live would be in Greensburg, or in Irwin, or North Huntingdon Township, or Murrysville... or in Allegheny County, you could live in Monroeville, Penn Hills, Wilkins Township...
This area has such good housing values and so many friendly small towns, you_ll love it!!