3rd vote for Denver. I lived there. It has everything you just described, with the exception of mild winters. Denver winters can be harsh and snowy at times, but they are always mixed with lots of sunshine and golf days too. It can get very cold, but its generally comfortable enough, just not quite San Diego winters. The snow usually melts in a day. The summers are warm/hot but dry, not muggy at all.

There are a ton of communities within 30 minutes of downtown that offer a wide ranges of lifestyle and job bases nearby. The northern suburbs are more spacious, less crowded, newer. Southern burbs are tighter and older, but there is a lot of variety. Denver Tech Center is down south. Golden to the West is also nice, newer and popular and only 1.5 hours to world class skiing, Breck, Aspen, Vail, etc.

There is a specific neighborhood in Erie (20 minutes NW of downtown) called Erie Village that has all Victorian and Prairie style architecture, large lots with the garages in back or side, and HOA specifically permits and encourages granny flats. Its a beautiful little planned community, HOA fees are about $40 a month. Huge, newer (2000’s) homes going for $400K to $600K with large lots (plenty for a garden).