The other way is to take 680 to 580 east to I-5 south, and turn right on Del Puerto Canyon Rd. This route is more miles, but takes the same time (about 2 hrs) as going over Mt. Hamilton.
Overall we had a great time at the park, but did not have a chance to explore it fully. We came across a couple of sections where the trail had washed out, and the top soil that was left was too slick to hold the vehicle. If we -had to- get by, we probably could have, but sine we were just out romping around and had no set path to take we chose to bypass.
We found a Park Ranger near the entrance when first entered the park, and talked to him for awhile. He told us not to come over on rainy days, because he usually closes the park to 4WDs when it starts raining. At first I thought he was being over cautious, but after Jack and I got out on the trails and discovered just HOW slick the top soil really was there, I understood the need to close the park. Even with the light sprinkling of rain that fell in the morning while Jack and I were there, the top soil got extremely slick.

(as
far as I know) There are no maps available, like you get at Hollister or
Pismo dunes. Also we did not see a single marked trail, so I can
only assume none of the trails are named. We started the day by exploring
the trails at the lower elevation. Even at the lower elevation we
came across several hills that were too steep/slick to climb. Both
Jack and I have 33" MTs, and lockers front and rear, but were still unable
to climb some of the hills. I'm sure if the ground was completely
dry we would have been able to climb them.
The pictures are not in very good order in this trail report. Jack and I started off the day exploring a large portion of the lower (elevation) of the park. Then we took a VERY STEEP muddy trail up to a higher section of the park to have our lunch, and keep a bird's-eye view of the park so we could see if Amondo and his friend had arrived. They arrived at the park while we were eating, and we decided to go down and meet them since they wouldn't be able to get up to where we where. (The Jeep had balding tires and no lockers)
After we met up with them we decided to talk them we decided to take the same loop we had taken in the morning hours, since we were fairly sure the Jeep would make it over that route. Instead of keeping the pictures in chronological order, I decided to put them in order as we tackled different sections of trail.



Most
of the pictures are actually taken on steep terrain, but the camera doesn't
convey that very well. Here Jack takes the hard way down, over a
rutted section of trail. Jack's pick-up has Detroit lockers front
and rear, 4.88 gears, and 33" BFG MTs.


Here
Amondo takes on the same section of trail. Amodno's FJ62 has ARB
lockers front and rear, 4.88 gears, and ARB and Kaymar bumpers.
Nerf bars are still in the works, as is some rocker panel protection for
the rear of the large truck.


Here
I am playing on the same section of trail. I parked in the rut for
awhile with one of the back tires a couple inches off the ground, so I
could take a look at my rear suspension. I realized I still had not
removed the Rancho spring clamps that I'd been meaning to remove, and that
my shackle bolts were a bit too tight to let the unbraced shackles work
their magic. I pulled out the tools, loosened the bolts, and removed
the Rancho clamps. By the time I was done the wheel that was hovering
above the ground was now touching! Wow... talk about fine tuning.
:-)

Here
I am climbing a rock down by the creek.
Next
Jack climbed the rock, but since his tire was caked with mud he slid off
the rock, and landed on his lower control arm. Not to be out done
I pulled this same move in the afternoon, but was stuck much worse.
I ended up pulling the Hi-Lift out to ease my truck off the rock.
Whoops :-)

As
I said before we didn't get to see the entire park, but we did like the
part that we did explore. The park is not quite as nice as Hollister
Hills, but it is definitely worth visiting. We plan on going back
for another visit when the ground is a bit more dry. Unlike Hollister,
no air is provided. If you don't have on-board air, the nearest fillup
is 17 miles away in Patterson.