I started looking into traveling the world in older times due to some worldbuilding I've been doing, and this came to mind. Traveling was not something that was done by your common people, I would assume, but are there instances of people traveling across the Empire for pleasure reasons, like we do on holidays? How would such a travel take place, by horse and cart, on foot? And how long would this take?
Say you were to go from the easternmost point to the westernmost point of the Empire, that would take a considerable amount of travel time, would such a journey ever be conducted, and if so, what reason could it have? Did common folk travel at all to faraway places, and if they did, was this on foot or by horse?
Well have I got a thing for you!
Probably the closest thing to modern mass tourism would be pilgrimage, but elites certainly could travel for pleasure, and many did have "vacation homes" in places like Campania (cf John D'Arms famous Romans on the Bay of Naples). It is also possible to think of something like Pausanias' Description of Greece as being both a travelogue and a travel guide, thus implying something like tourism.
I will note that sometimes there is reference to Sparta becoming something of a "tourist park" for visiting Romans but I am honestly having some difficulty finding the source for that (the reference on Wikipedia is incorrect).