While I agree with mass transit all around (I've lived in a couple of different major metros other than Denver), I don't see the population density one would normally associate with a longer distance like that ... I know the whole region is growing, and it is better to build now than to suffer later.

As a bit of an outsider looking in, I think 93 could use an upgrade no matter what.  Really pretty drive, but I know it is treacherous and trafficky.

A country like Germany might put a tram between Golden and Boulder.

Seattle has built trams, my favorite was built in one of my old neighborhoods, Lake Union.  It was the S.outh L.ake U.nion T.rolley before the city government realized what the acronym spelled out.  Some of the local independent coffee houses came out with t-shirt, "Ride the S.L.U.T.!!" ;)