You can walk around the area in maybe 4 hours. I would find it hard to imagine you spend more time EVEN if you have a guide. Most of what you see here are churches, much uglier than European based ones, and the main interest is that they were brought here and thus brought Christianity to the area.

It's also confusing if only churches are inscribed or the entire area. The local signs will guide you to the UNESCO Viceroys Arch, Adil Shah Palace Gateway which is in front of the perhaps Cajetan (locally called Church of Divine), the Archaeological Museum, but since it's not far off what you visit anyway you can take the quick walk down.

I started with the largest: Bom Jesus. It's one of three old churches still actively used nowadays. It also says no guides are allowed inside but I saw a couple enter the Cajetan church with one so it might not be a big deal. As I mentioned before the churches aren't grand in any way. It's true that this one is large, has a courtyard, many places to visit, but I still managed to get through all in a short time. I actually spent most of the time in the back garden (near the toilet) because it was idyllic - the toilet is still a bit off so don't get the wrong idea!

Afterwards it's time to walk a bit further. The St. Augustine remains won't take long to check out. This is the only church with only plaques and an altar, perhaps some broken walls of the tower if you want to count that. The church of the Lady of the Rosary nearby looks closed from far away but you can actually walk around the gate, legally and meant to do that, and there was nobody here at all. The church isn't in use anymore so it will be quiet. Again, not much to look at but the view FROM the garden is not bad.

After grabbing some refreshments on the way to the St. Catherine, St. Francis Of Assisi and Se Cathedral block. All these are easy to get through because their area is quite small. The latter seems larger and is quite enormous. St. Catherine is super small, St. Francis is only a facade more or less. There is the Archaeological Museum of Goa museum nestled next to the entrance if you want more background on all these.

When I was finally done, and still confused where the Cajetan church was, I walked east and saw the arch, gateway and the Church of Divine which is the local name for Cajetan. There was once again a modern looking church, still in use today, but almost no tourists. I believe the tourists will only be arond Bom Jesus and the cluster of three (even St. Catherine is "off" for them though). If I had really been fast and just looked through these the usual Zoe way then it would be maybe 2 hours plus the walking in-between the churches.

While I understand that these are important for the spread of Christianity I don't know if staying in Goa is really worth it just for that. There is enough to see in the area around it (and Vasco da Gama itself) to make it worth it visiting though.