We were there earlier this year, though not cycle touring - only a day spent cycling, but I would say it's pretty cycle friendly. There were plenty of solo cyclists out and about, even on the main routes, and the traffic is very accommodating. Roads other than the main routes don't tend to join up so to get anywhere you will be on the through roads.
Finding places to stay is fairly easy, even away from the gringo trail, and camping is fine (eldest shallot travelled there with a hammock a couple of years ago and was fine). Connections by air may be possible, although the planes are more like a bus in the cabin people seem to take loads of stuff and the charge for hold luggage is free or small. Absolutely no way would you get a bike on a bus.
Things to bear in mind:
The standard of road surface is *extremely* variable. Take a look at the two main routes from Bogotá to Medellín marked as "interstate" 56 and 60 on Google maps - one is perfect smooth tarmac with a cycle-able hard shoulder, the other looks like a farm track! Away from the main roads it's pot luck whether you get tarmac or something rutted like a stormy North Sea.
It's hilly. Very hilly. Imagine you take a normal hilly landscape in panavision and display it on a 4:3 aspect ratio - that's what Colombia looks like.
You will need some Spanish.
