We did this hike on May 15, 2005 and the bugs at the top are bad. They are not masquitos but little nat like things that just annoy you while you try and rest and eat lunch. But other then that it is worth every drop of sweat.
There is no signal at the intersection of Live Oak and Satiago Canyon. The signal is at Ridge Line and El Toro, however, if you get to that signal you have gone to far. You turn left at the stop sign at Santiago and Live Oak, towards O'niell Park.
Adventure Pass box is no longer functioning at the parking area. Apparently out since May 2007. I did see at least one vehicle with a ticket from the ranger when I got back. Also note that Santiago Canyon Road is available from the Toll Road 241 if coming from Inland Empire or Tustin/Irvine. Great information--very useful--and I enjoyed the day.