https://www.google.com/maps/dir/39.5800626,-104.8864011/Dry+...
This isn't a "last mile" problem it is a problem with this urban form, which cannot be effectively served by transit. It's hard to believe anyone put a rail station here in the first place. It must have cost a fortune, especially with that multi-story parking structure.
Probably the best thing that could be done with this site is take the rail station as a blessing and level all of those office parks within a mile of the place, building up a walkable transit village instead. You could easily put several thousand residences in that area instead of what appears to be a shitload of surface parking.