FWIW I'm worried that Gardner could easily be the cycle's Rob Portman.
I doubt it, Rob Portman was in a tilt R state, which got even more R, and was rather popular, or at least lukewarm with the public. He was able to get support from the unions, and position himself excellently as conservative on social issues, and populist on economic ones, even though he isnt.
Cory Gardner is in a tilt D state, which is getting even more D, and is hated, being one of the most unpopular senators in America. The only issue he has to appeal to CO voters is the fact that he likes Marijuana, but I doubt that will be enough.
I think hes DOA, unless the CODEM really messes up. While Incumbency usually helps out a candidate, it can be a double edged sword if you happen to be unpopular, and without a base. In my opinion, Jones is in a safer position than Gardner, but thats a post for another day.