[MENTION=72375]Palal[/MENTION] - thanks, great information.

As it turns out, TAP changed their schedule and added an additional LIS - FCO flight that afternoon. My original flight was pushed back an hour, which now means I have a 5:40 layover. That certainly allows enough time to safely leave the airport. But I can also switch to the earlier connection at no cost. I'm not sure if I can change the flight on the actual travel day, but if so, I'll decide after clearing passport control (and based on Lisbon's afternoon weather).