Have you ever visited the Llano Seco Unit? It is a scenic place to take a leisurely walk, with or without small humans. The toddler had a great time running up and down the wooden ramp/platform area. There are plenty of birds to watch and listen to and its a pretty sweet place to watch the sun sink slowly into the horizon.
He also discovered the mother load of all puddles and would have been perfectly happy just stomping and throwing pebbles into all afternoon.
Beware--it is WINDY out there. It wasn't terribly cold just super gusty so dress accordingly! Next time we go we will pack a snack or two and some steaming hot cocoa to enjoy on the viewing platform.
Check out their page for more information on Llano Seco and for easy directions. It is just a short 15 minute drive West of Chico.