Another one not to be missed is Len's Train Shop in Irwin (be careful, GPS / Google Maps puts his address in wrong place).
Other ones in the Irwin/Jeanette/Greensburg area are Niedzalkoski's Train Shop in Jeannette (limited amount of O gauge), and Dick's Train House (Greensburg address, but closer to Jeannette).
If going to Patrick's in WV, there is also Chippers Trains in Washington Crown Center Mall just off of I70.
Andy