You’re likely to become very familiar with it in the early levels of Tomb of Annihilation, as the adventurers search for clues.
It’s easy to become distracted by the rules given on the adventure: Roll three times each day to see if an encounter occurs, then determine what it is.
The problem with this is that it eats up time and can lead to very boring adventures. It does depend on the group. I was very happy when younger to kill them randomly generated monsters. If you’ve got a group who enjoys a variety of combats, then the random encounter plan can work very well for you. It’s not good with groups who are more interested in the story; having sessions of combats that don’t advance the story tends to be frustrating.
However, it also depends on the situation. What are the group trying to achieve in the jungle?
Three situations come to mind:
- The adventurers are exploring blindly, looking for something of interest.
- The adventurers are looking for a specific location, but they don’t know exactly where it is.
- The adventurers are travelling to a specific location and have directions.
It’s the first situation that makes the best use of the random encounter tables. I’d prefer it if Chult had more keyed locations in the jungle to investigate – in a home game, I’d fill it with ruins and other items of interest – but the random encounter tables do allow you to have something happen as they travel. As an alternative to rolling three times per day, you could determine one encounter for each new hex they enter that doesn’t have a keyed encounter. You could also alter tables to give a chance of finding random ruins or a settlement. Finding such fleshes out the map with permanent features, which the adventurers can revisit later.
The third situation has directed travel through the jungle: you use the jungle as an obstacle between the players and their destination. Using too many random encounters in this situation is most likely to frustrate the players. The first few encounters are fine, but playing eight hours of encounters before they reach the destination is probably too much!
There’s a reason Order of the Stick describes how there is only ever one random encounter during travel!
When the players know where they’re going, you want them to have a few encounters to demonstrate that the jungle is dangerous, but not too many to detract from them getting to an interesting area. Depending on the time you have and the length of the journey, between one and four encounters seems appropriate.
The second situation I’d handle with a combination of the two techniques: only a few encounters on the way to the area the adventurers wish to search and then you roll one encounter per hex explored.
You can use these techniques in any adventure with a lot of travel – Out of the Abyss also comes to mind – but they are very useful in Tomb of Annihilation. You should also look to the advice on page 106 of the Dungeon Master’s Guide on running travel montages and hour-by-hour travel.