Okay, being both Portuguese AND Catholic (and having a daughter whose middle name is Jacinta, after one of the girls at Fatima), perhaps I am a bit biased
, but I’d like to weigh in on this topic...
You definitely need to stay one night in Fatima if you’d like to experience the site, even if you are not Catholic or religious. A brief bus tour stop in the plaza would be depressing as it’s large, vacant, and just a whole lot of concrete. On your own, you can visit the museum, each separate chapel, walk through the stations of the cross to the original village, and even walk to the town where the children were baptized. It’ll be a good warmup for your pilgrimage and give you a sense of the area beyond the “you got one hour!” tourist blitz at the main site. The evening procession can be quite moving, even for non-believers, as witnessing large-scale expressions of any faith is mesmerizing. Fatima is no Lourdes (now THAT place is definitely a pilgrimage site to experience), but it’s worth 24 hours of your life.
We traveled by cheap bus from Santiago to Porto to Fatima to Lisbon, taking a few days in each place - the reverse route is certainly doable, but bus service is somewhat limited. I’d encourage you to definitely slow your pace (if possible) and be present in each of those cities for at least a night or two in order to see them at all hours, especially since they really do change during the course of the day.
As for the person who said one week in Porto seems like too much? SHAME!!!!!!
. I could spend a lifetime there and still be happy.