Many state game lands are smallish lots with uneven borders, and "islands" of private land within. There are a whole bunch of them spread all over the state. And many are very different from one another, i.e. this one's mature forest, this one's a bunch of brush, etc. Overall, when compared to say, the National Forests and State Forest system, SGL's offer much more small game opportunities. Some state parks offer this too. But the state and national forests offer much larger plots of largely mature forest, with mostly big forest game (turkey, deer, bear, etc.). Also, there are large tracts of land owned by timber companies and other businesses, and hunting and fishing are generally welcomed and any exceptions often well marked.
Here's a map for SGL's. The little green areas are the SGL's. When you click on the map, it takes you to a zoomable google-maps type interface, and the SGL's are then orange. As you zoom in, they switch to black borders. Access points (official PGC parking) are also shown.
http://www.portal.state.pa.us/portal/server.pt/community/state_game_lands/11363
Don't forget that we have an awful lot of private land which is open to the public as well. The state law is that if there's nothing indicating you can't go there, you can go there. But if a landowner tells you otherwise in any manner, whether it be signs, verbally, smoke signals, etc., then you can't. There's a lot of old wives tails about signs having to be signed, spaced