Online is best, although some paper trail maps at be available on site. In any case, it is one of the best camping sites in the Northeast.
They normally have some at the trailhead parking lots but I was there yesterday and there were none left. So print them from the website.
http://m66.siteground.biz/~morrispa/index.php/parks/mahlon-dickerson-reservation
Thanks! Your answer is awaiting moderation.