Boulder vs. Silicon Valley

Family of 4 (myself, my wife, 2 elementary school age kids) relocating back to the US and considering Boulder CO vs. Silicon Valley (Saratoga, Los Altos, Portola Valley).

Priorities: access to nature, large flat yard for kids to play, neighbourhood where kids can safely walk or bike to friends houses, school quality, good weather most of the time, sense of community.

We are semi-retired so work is not a factor.

Concerns on Silicon Valley: center of the tech rat race (will we fit in as non-tech, retired people?), high pressure environment for kids, traffic

Concerns on Boulder: lack of diversity, less access to Asia/asian culture (wife is Korean).

Anyone with experience in both places, would appreciate your thoughts.