Best way to see Nazare Obidos Fatima

It looks like there’s a direct bus from Porto to Fátima (2h). Spend the night: https://booking.fatima.pt/en then take a direct bus from Fátima to Lisbon (1h 30m).
I believe you can day trip from Lisbon to Nazaré by direct bus (1h 45m) and Óbidos (1h).

We spent nights in both Óbidos and Nazaré and we had a rental car. Nazaré is about midway between Fátima and Óbidos so would make a logical overnight stop. Óbidos can be seen in a couple hours while Fátima can take between 1.5 hours if you want to just see the sanctuary to a half day if you want to visit where the children lived and where the Angel of Peace and Mary appeared.

We were staying in Tomar when we day tripped to Fàtima and Batalha monastery, and stopped at Alcobaca monastery between Óbidos and Nazaré.

That time of year you’re likely to see the huge waves in Nazaré that the surfers ride, so it may be busier than one might think.

Thanks for the helpful suggestions. Really appreciate it! The more I read about this area the more it seems that public transportation isn't great in this area, so a rental car is recommended? Or could we take a train into the area and find a tour company to take us to some of the nearby towns?

There are many groups day tours from Lisbon covering these three destinations.

If you are comfortable driving in small European towns and associated parking rules challenges, then car rental would be cheaper and flexible. Main motorways are pretty straightforward. However, read up on car rental threads on this forum and elsewhere to avoid unpleasant surprises.

We considered both but went with the third option of hiring private car+drive, an idea we found suggested in this forum.

There must be many vendors that might be offering this service of varying price points and quality.

One we used was excellent and far exceeded our expectations

Cost for our family turned out less than group tour especially as we combined it with travel to Porto.

Convenience was so great that we are now constantly looking for similar reliable referral in other countries.

For us, because those locations were part of a longer trip that included many out of the way sites, we had a rental car. If only visiting as a day trip with a rental car, each of the places I mentioned has free parking. Look it up beforehand so you can drive right to it and save time. Whether you get a rental car, private driver, or use public transportation depends on how flexible you want to be regarding how long you intend to visit each place.

Since we had plenty of time, we took back roads most of the time and were able to avoid most tolls.