I think you'd have to further sub-divide California to get the full picture. LA and the Bay Area are worlds unto themselves in terms of culture, and probably do have more in common with Europe than Iowa. The rest of the state is much more typically American.

Having raised a 3 year old in the Bay Area (SF and Albany/Berkeley), I've anecdotally noticed a lot less of the puritan/sheltering attitude you're talking about than in other places in the US. I'd say a moderate version of 'free range parenting' is actually the dominant trend these days around here.