A few years ago there was a really great homeschool East Bay 4H group that we did stuff with for a while. Given the nature of kids, and growing up, they may have fizzled (or grown, I have no idea.) I know Monsanto may be supportive of some stuff, but I think there is a lot more diversity in individual 4H groups and less connection than BSA has with the parent organization. Or not... not sure. I'm sure you'll examine it as you get closer (although, that said, there were a couple of people with babies there, too...)

And yes, the East Bay Regional Park stuff is really pretty awesome, too.