Well, Gangelt showed 15% had antibodies (subject to, potentially fair criticisms re: methodology) so I think it's fair to say it varies by locale.

While I understand that many folks from Wuhan travel all over the United States, the non-stop options from Wuhan to NYC and, if I recall correctly, SFO and LAX meant that more opportunities existed for early spread than the middle of Colorado. In fact, I can't actually pinpoint a city in San Miguel County, Colorado -- can you? (https://goo.gl/maps/F7CJ3yfDKaf1gQjDA) I guess there's a post office in Egnar... Telluride maybe?

Certainly the sparse population created natural social distancing precluding its spread.