Those aren't weird routes for UAL 757s at all...OMA
has had 757 service for years and years, with DC-10s and DC-8s prior to that. COS
had 757 service off and on for several years also, especially during the WestPac days. DSM
, being a smaller market seems like an unlikely route, but has also been a recipient of 757s for at least the past 7 or 8 years.
Albuquerque, Greensboro, Manchester, and Providence are also small-medium sized markets that have/had UAL 757 service.
To most people, the sky is the limit. To those who love aviation, the sky is home