So as Kevin Flynn said, hours on the grid were like minutes in the real world. So if in the real world he was gone for 20 years, Kevin's "grid time" must have been at least 200 years while only aging 20. Damn. 200 years is a long time to hang around. No wonder he had to develop a "zen" thing. However, you'd think with that much time Kevin would have thought of something to get out of the grid.