Miles of FS roads right off the main park entry road, 347, before you reach the park entrance.  Roads are pretty rough, but pick a site not too far along if you have a trailer.  I would not suggest trying to drive your class C or A in here-go into the park and pay for a spot.  Check conditions-muddy or snowy would definitely make access tough.  I went to watch the Leonids meteor shower (sad showing) and found a great spot open to the sky.  Plenty of spots with shade as well.  Endless hiking along the roads.

Please leave your site cleaner than you found it.