^^ I loved Locust Lake when i was a kid. Im not to far away from the campground, so it was our 'go to' place. Easy bike trail around the lake, beach, hiking trails boating etc etc..
If your looking for something other thn a campground. Schuylkill County (Pottsville, Minersville, St. Clair) area has many easy miles and miles of trails.
You can look into "Reading Anthracite Offroad Area" which (requires) a yearly permit... I have yet to run into anyone with a permit tho :/ RAOA website or google should get you maps of the area.