I had some errands to run beforehand which put me in at the northern entrance to the park (a map is available here, but be aware that it does not have the trails labeled as they are named on the park signage). Unfortunately, most of my pictures somehow got corrupted, but I have a few that came out!
There is a road that runs through the center of the park, by a couple baseball fields and a public swimming pool (which I am totally taking advantage of soon). The trail meets about ten feet back from the main parking lot, and I hopped on it and headed left, because it seemed as good a direction as any to go.
I hopped onto the trail on the TARDIS because despite what other people think, I'm not going to let my lack of an actual mountain bike keep me off the trails. For god's sake, when I started hiking I routinely wore flip-flops out of pure and simple "Don't know no better." There is a main trail that encircles Walnut Creek that is only marginally less smooth than a fire road, meaning the Surly is more than capable of tackling them. Whether or not I am is another question entirely!
Not to be a walking advertisement for Surly or anything, but it blew my mind that despite the fact I was riding a road-touring bike with street tires on it, my bike really didn't handle any differently despite the surface. It's an incredibly stable bike and it's fun to ride even off road. So, way to go Surly.
I didn't ride very far, I admit, mostly out of insecurity, but also out of the fact that (as usual at this time of year), I was getting the beginnings of heat exhaustion. And, as is often the case with the wrong tool for the job, every time the trail got technical (I got lost down at least one side-trail), I opted to hop off the bike and walk it. I think with practice, to be honest, most of the sections I walked are perfectly doable on the Trucker, but I also admit that there are far more ideal bikes for the task. If anyone has any spare cash sitting around, the Santa Cruz Juliana is a pretty good tool for the job.
I eventually got to the point where I was getting a bit concerned about my ability to press on, as I could feel my head getting lighter and my heart beating faster (for those who live in cooler climates, this is a sign you need to cool off NOW). I asked a very kind fellow on a super-sporty Trek and he gave me directions back to the parking lot. Once there, a very nice lifeguard let me hose myself off and fill up my water bottle afresh, which improved my morale quite a bit for the ride back up the hill back to the house. I unlocked the TARDIS, swung us back onto the pavement where we usually play, and headed home.