Bjork, Beasties, Arcade Fire, Interpol, Neko Case, Spoon, The Hold Steady .. & they'll keep stacking this bill through April. I'd definitely expect to see a ton more PDX & SEA bands added. They had to lock in their headliners early.
End of May, everything's running on both sides of the Cascades .. though George is a bit of a haul from the mts. If I were in CO, I'd be clamoring to get on this trip .. but I'd guess being that you are
in CO, you'd have a better response if it were widespread Panic or String Cheese Incident or something like that.
Good luck & if you make it up here drop a line.