The PA Grand Canyon, or Pine Creek Gorge, begins near Wellsboro and streaches 47miles south, with a maximum depth of 1450 ft. at Waterville near the southern end.
If you google search, PA Grand Canyon, it will give you probably more information than you ever wanted to know.
From a riders point of view, Rt. 6 that runs east-west across that area can be a nice ride. It is especially beautiful thru Tioga and Potter Counties
Don't know your direction of travel but, going west along Rt6, The ride from Galeton to Renovo down Rt 144 is a fun ride with plenty of twisties. Really, any of the main traveled roads in that area will give you more than enough riding that will test your skills, as well as enough beautiful scenery to keep you happy.
Rt 120 out of Renovo over to Driftwood is fun, then 555 takes you thru prime Elk country over to Weedville.
Do some online research as that is a primarely rural area and motel accomodations can be few and far between.