Looks like some good stuff there. I have included a lot of trails in my new map of NJ (which I hope to upload later today
), but I will look through some of the stuff here for inclusion in the next version. Surprisingly, I've found that some of the old paper parks maps I've collected are actually quite accurate. I scanned and georeferenced the Belleplain and Lebanon maps and was able to trace pretty good trails from them. Others, like the map of Wawayanda State Park, are too small to be accurate enough.
Looks like that site has a nice collection of scans of the old paper maps. Have you seen
http://www.everytrail.com ? They have some .gpx files of NJ trails, but not a lot.