Depending on the time of day, you could use their rail transit to go downtown Denver Airport Train & Light Rail | VISIT DENVER Getting from DEN to downtown Denver has never been easier. Ride the airport train for only $10.50 each way. Learn more! www.denver.org
Not boutique but the Sheraton Grand and Renaissance are both walking distance to Pikes place and other stuff. Marriott Bellevue is also nice, not Seattle though.
I know your style, my man. You’re welcome: Ace Hotel Seattle | A Belltown Seattle Loft Hotel, Downtown Adjacent
Denver Airport Train & Light Rail | VISIT DENVER