Transportation
I stopped in the airport for an overnight layover with TAP. They have some comfortable couches that you can grab if you get there early enough. They stopped me from going into the international terminal because there was less stuff to do, but there was construction near the couches when I was there so going into the international terminal would have led to a much more peaceful sleep even if I didn’t get a very comfortable couch. There are some shops in there that open in the morning too, so grab dinner and then head in to have the night to yourself.
What I would do differently
Cough up the money for a flight without a layover.