I, and nearly everyone in my neighborhood let our kids out. I see kids walking up and down my street, by themselves and with their friends every day. Let your kids go out, they and you will be fine.
Here in the bay area, I only know 1-2 areas that are like that, and even then you'll only see teenagers. Might end up moving if one is local! I'm in the lower peninsula area.
I live in Washington, Puget Sound Area. Kids out all the time, plus no income taxes, reasonable property taxes, and a great, though limited tech scene.
The PNW isn't for everyone, but we know how to get outdoors at all ages :).
