This will likely come as you play the game, as there are way more caves than are needed for the achievement. You do not need to traverse/explore the entire cave to get credit - simply going far enough in for the name to display is enough to get credit. You can get your current count in the Pause Menu by selecting History, then Adventure Logbook, and then Exploring the World. It's the last entry there.
You can also use the following map for all the locations:
https://mapgenie.io/dragons-dogma-2/maps/world