Thanks Hillbasher. We'll try that next time. For what it's worth, we made an attempt at it. I pulled a Burley while my wife trailed us and kept an eye on traffic. Traffic wasn't all that bad, but more than I hoped for. We did a healthy bit of climbing up to the start of the 2nd reservoir before turning around. We came back down the hill and rode the river trail around Santa Fe Dam before heading back to the car at Encanto Park. Overall, the 26 mile ride pulling a toddler was actually a lot of fun. She slept for most of the journey on 39.
I guarantee that you will like it. Once you get in about a mile in on the West Fork, you leave most of the people behind. Only ones you will see will be on foot or bikes. It is closed off to all cars except the one or two that cabin owners might have back there. The chances of seeing them or any of the workers from the damn in cars is very slim. An exceptional ride in the spring when the water in the river is higher and everything is green from rains. But even this time of year, it is worth it.
We did a lot of riding in the area last weekend. Actually we were camped at Camp Williams on East Fork so we started out from there. I did Little GMR early in the morning before my wife woke up, then we rode up 39 to the 5000' sign. After descending 39, we hung a right onto the path towards Cogswell.
When we take our daughter up there, we'll park at the parking lot at the entrance to the path. There were actually lots of people parked there. The path was filled with walkers, joggers, hikers, fishers, and parents with kids on toddler bikes. The river was flowing, and the trees kept the path nice and shady.
If you are on a mountain bike, you can reach the top of Mt. Wilson from the road up to Cogswell. Ends up being a long ride, but goes through some nice area. Not sure anymore now after the fire, but it used to be nice.