Did you check the "Where to go section" on this website?
It contains a lot of airfield guides, and Bogota is also listed and freely accessible for non-members; it will probably answer most of your questions.
Best places for non passenger,
* Corral Hamburger restaurant, upper floor has some tables out of view of the general public.
* Mc Donalds, though the views from the foodcourt next to it no longer offers viuews of the runway.
* Get access to the Airforce museum
Walk out to past Avianca terminal to the old hanger area.
Easy to snoop around.
At the end of the hangars cross the main road, and check out the New cargo ramp.
There is a hotel here but no views from the rooms avail.
Passengers from the Avianca Domestic terminal have good views, the only views of the AeroSucre Ramp, full of 727s
Great airport !!
* for passengers, get access to Avianca domestic