I am from Michigan, and lived in southeast PA for 14 years. It's nice. And totally different than Michigan, topography-wise and culture-wise. Good on both accounts, and very different on both accounts. I am familiar with SE and SW Michigan, pretty intimately.
Land and outbuilding will not be found affordably (compared with MI) near Philadelphia, or near Harrisburg or Allentown for that matter. Michigan real estate prices are several notches less expensive than anything in eastern PA. The big game changers comparing SW Michigan to SE PA are New York City, Philadelphia and Washington, DC. The population density is completely different. Chicago has no relevance and no effect on SW Michigan real estate, except for Lake Michigan property.
Your best bet for low(er) prices in relative terms in SE PA is between cities, ie the Lebanon area, or in central and northern PA where population is less dense. Have a look at Berks County. Nice proximity to everything and a bit lower priced than Phila and the Lehigh Valley.
Lower priced counties: Berks, Lebanon, Lancaster. Although Lancaster is heating up, and desirable places in Berks are getting hot.
Higher priced counties: Delaware, Bucks, Montgomery, Chester, Lehigh, Dauphin.
Where exactly do you want to be, relative to family?