Are there any alternatives to Greyhound bus lines for Michigan?

I'm planning on visiting my friend in Pennsylvania sometime this week or next week and the only available bus schedule they have is for Sunday and that involves a 4 and a half hour layover in Pittsburg which makes my mom nervous so I can't do that. Well my friend called and they told her that's the only one they have avaiable from Michigan to PA through October. So that won't work. Does anyone know of an alternative to Greyhound for my trip? I can't do Amtrak that's too expensive so any other bus lines? Or maybe trying another location in Michigan would help?