Have not been there, but the national forest map reports at least two gates, one about a mile north of Nate Harrison / S7 and the other past the observatory just before the "high point". I can't see the first one in google. You can climb over the second one unless it's been improved since 2009: https://ssl.panoramio.com/photo/21781198
There may be one or more gates in the immediate vicinity of the observatory.
I tried to go the other way some time ago and made it about a mile from the 79 (on a road bike!) About half of the road from the observatory to the 79 is supposed to be paved. The rest is sand/dirt/gravel. MTB is optional but recommended.
This is on my todo list but I haven't dusted off my MTB for a while, so I'll have to pass.
Last edited by hamster; 09-26-13 at 06:55 PM.