At present I am running both a Forbidden Lands campaign and the D&D 5th campaign Tomb of Annihilation, and it gives me two different experiences with hex crawl gaming, and that has been illuminating. I have not played anything using a hex crawl element as part of the adventure for decades, not really since I played X1 Isle of Dread. Usually I play with systems using something closer to a Theater of Mind travelling such as when playing The One Ring, Hinterlandet (The Hinterlands) or even Traveller.
Now we are moving hex by hex across the map, and it is interesting and somewhat different from what I am used to playing, and setting up D&D/Tomb of Annihilation against the Forbidden Lands RPG interesting.
Hex Crawls seems mainly to be a part D&D game (for instance, there rules for it in Warhammer Fantasy 4th edition, though the campaign we are playing right now spends a lot of the time on the road), and mostly within the OSR-subset of the D&D game. I therefore do not have much experience with it, and it was fun and a novel experience, when we began playing Tomb of Annihilation.
In Tomb of Annihilation you have a large empty map, much like the Isle of Dread map, and in some hexes there are fixed encounters, but the majority of the hexes are empty, and you have to travel rather far to find the fixed encounters. Luckily there are extensive random encounter tables with the campaign, so when the adventurers are moving from A to B or moving into unknown territories, the tables are used to generate encounters.
The good thing is that many of the encounters can be played as something other than a straight combat. You meet creatures or people or some stuff, they left behind, and you can interact with it. The bad thing is that all of this are still travelling creatures. You do not encounter villages, towns, dungeons, ruins or large groups of creatures like 40-100 orcs, that you have to flesh out as a larger situation. If you play the adventure as it is, there are only a few meaningful encounters and ruins tied to the larger story, and the rest of the hexes are just empty spaces, where you may encounter something moving about at random. The land in Tomb of Annihilation is largely empty. You could ofcouse begin seeding every hex with something more than a hunting party of goblins or a hungry plesiosaurus, but you are not given any tools by Tomb of Annihilation.
Secondly, when travelling, there is not much to work with, when it comes to navigation, survival and foraging. The players can choose between moving fast, slow or medium, which affects their chances of navigating succesfully, but unless a harsh deadline is looming, there is no reason to travel fast. When travelling the characters daily perform a navigation test to see, if they get lost or not. This replaces the roll of a die to see if the party is lost mechanic from older editions. When it fails, the PCs travel into random hex and they are now lost, until they can find landmarks or otherwise succesfully gain a sense of their location. However, this got boring fast, as the only real consequence, when travelling through a mostly empty map, was more days spent in the wilderness without getting to the exciting stuff.
This was where Forbidden Lands became the much better game. Forbidden Lands is contains a lot of empty spaces, but the scale is smaller, so larger areas are traversed faster. Secondly, the players have many more locations to point at and choose to travel towards, and as a GM you are given bunch of locations (especially if you are using the Raven’s Purge and Spire of Quetzal material), that are not fixed anywhere on the map. Instead you are given a legend, you can tell the players, so they might decide to go and explore, and you have a bunch of stickers, so once a location is found, you mark it on the map with a sticker permanently altering your map to your specific campaign.
Suddenly exciting locations jump out of the map, as you can easily stick something to the map, where you want it. The adventure invites you to do so. There are still random encounters to introduce during the travels. The adventurers will meet other travellers, and in most cases these travellers are people on their own errands, such as a bunch of orcs transporting a captured orc or a spooked horse with an empty saddle. These invite the players to roleplay and problem solve, rather than declare initiative, and that gives us some great play.
Secondly, when travelling, there are few more choices to be made. As in The One Ring the party members have their assignments when travelling and setting up camp, this keeps several players active, rather than the one rolling the navigation test in D&D/ToA. When a roll fails, it does not result in the PCs getting lost, but rather in an unfortunate event depending on the kind of roll that failed: Leading the group, scouting, foraging, hunting, setting up camp etc., each triggers some kind of situation, the players must deal with, and which may cost resources. It is a bit like a Fail Forward mechanic, where you still get closer to your goal (which you do not in ToA, when travelling in a random direction due to a failed navigation test), but the failure comes at a cost.
While neither Tomb of Annihilation nor Forbidden Lands necessarily gives you the exact OSR hex crawl experience – if such a thing exists – one of them is the superior, when it comes to playing travels in the wilderness, and I have therefore adapted Forbidden Lands travel rules to my Tomb of Annihilation campaign.
It means that extra challenges will occur in the game, but without spending a lot of time travelling in random directions on the map.