I've had my headliner out, and it looked fairly accessible. Remove all knobs, controls, vents, etc. The pitons that hold the headliner up are easily removed by pushing in the pin in the center of them. It did take me a little while to figure out everything that needed to be removed, but it was not a difficult job. I don't remember if you can get all around the evap, but i'm thinking a shop vac would do a good job up there once you have the headliner out.