I rode up Hurricane Ridge on the fixed gear at the end of July, 2010. Here's a photo at the top.

https://lh4.googleusercontent.com/-W...ngeles+030.jpg

It wasn't difficult on the fixie, so you'll have no problem with a geared bike. I do recall that I had to stop at the park entrance and pay $5 to get in, same as the cars. This was on a weekend, but traffic was not heavy. I forget how long it took to get up. I flipped the wheel around to the freewheel side for the ride down, but it was hardly necessary; it's just not that steep!

Luis