I don’t know anything about traffic across Lisbon, sorry. When we were in the Obidos area we visited the monasteries at Alcobaca and Batalha, spent a few hours in Nazare and Fatima. The best restaurant we ate at in Obidos was Alcaide. Our choice was to visit the other places during the day and go to Obidos in the evening when it was less crowded. Worked well for us. We were there the same time you are going and we enjoyed the festival parade in Lisbon.