The DEN F/O Guppy fleet in considered to be slightly understaffed. Every base and seat across the system in 2014 has had movement (it seems - maybe I'm wrong a little) except for Denver. Denver hasn't been a part of any vacancy bids in all of 2014.

So, if you wish to work for UAL and fly the Guppy and be based in Denver, it's gonna be a long time before a new hire could hold it.