Jay,
Lebanon State Forest, or BBSF as they call it now, has a relatively hard packed trail, the Mt. Misery trail. It is white-blazed and loops out of Pakim Pond. I think it is a 10 - 12 mile ride. It does have a couple of sections of sugar sand but you can ride through it. There is a short trail from the Ranger Station to Pakim Pond. It is the Cranberry trail with red blazes. This is a hard packed trail and has been cindered in places. These are the bike legal marked trails in forest.
The trails in Wharton are not as well marked. There are some people working with the Forest Service to try to map out and mark some trails. A nice section was marked and then it was used in an enduro. It is a rough sand slog riding it now. They have a sand road ride marked with blue blazes.
Kings Grant, Idon't know that well. I have only been there a couple of times. It was fun but I hear that it is a cold weather ride because of bugs and sand.
John