Your choice to exclude an outdoor installation limits your access to many signals.
I would concur with the Direct TV installer by recommending the
TERK HDTVi. You will need to experiment with placement upstairs or in the attic. Some brick construction is quite effective at blocking radio and TV signals.
KCWY-NBC is transmitting from Casper, WY about 135 miles NW of Cheyenne on real channel 12. You simply have no hope of receiving their signal. Their only translator, K28HL serves Shoshoni. It's further away and also far too distant and weak to receive in Cheyenne.
The only NBC station I find listed on your report that is available to Cheyenne viewers is KUSA out of Denver, CO. Reception would require a large deep-fringe outdoor antenna such as the Winegard HD7698P equipped with a quality low noise preamp.