I was just at Toby for a quick ride while visiting a friend.
The lake loop there is very easy, Frank Gantz trail is very rocky, and it will take you to Gouldsboro SP where there are a few easier trails like old Rt 611 For the most part not many mt bikers at these parks or trail maintenance. My friends and I are the only ones I have seen who do a bit of trimming, but the trails do need a revamp and more use.
With that said you won't find real good singletrack but there are lots of ways to hook up other places from Toby and Goulds using dirt roads. You can link to Brady's Lake, and Pinchot State Forest. Once again these places have no established trail systems. Not to say you won't have a blast just very different and old schoolish, but great if you wanna Gravel Grind.
Lots of stuff here with organized trail systems, riders, and clubs:
Wilkes Barre area, Moon Lake, Frances Slocum SP.
Scranton area, Merli Sarnoski, Moosic Mt, Lackawanna SP, Prompton Dam SP
Toby area stuff a bit further out Promised Land SP, Big Pocono SP, Dixon Miller Rec area, Delaware Nat Forest areas.
Ck Trailforks or MTB project also