AbdulAlhazred
Legend
OK, because the rules in 1e are pretty extensive and tie into a lot of stuff that is part of the game 'at large' I may not elaborate on every single bit, but I can certainly give you the nickle tour:Can you cite the rules that make 1e better than 5e for running hexcrawls? What are the procedures and loops that aren't found in 5e and make it better? Or if they are found in both, can you give examples explaining how the 1e version is better?
I've grown curious to understand how D&D hexploration has been designed in the past, compared with now. What has been carried forward. What altered and abandoned (with the hope also of understanding why)?
PHB contains the fundamental movement and light rules, these lay out what movement rates mean, what constitutes encumbrance (there are 4 levels of encumbrance, 5 I guess if you count 'cannot move at all'). It also contains the rules for Surprise, vision, etc. (though the DMG has its own, which aren't perfectly concordant with these). Equipment and some associated rules are also present in this book. The basic rules for mapping are also here (there's not much). Obviously the spell lists and descriptions, and some of the spell-casting rules are also found here.
DMG obviously contains the 'meat' of things! The biggest part of the system is found starting on P47 'Adventures in the Outdoors' (the first subtopic of THE ADVENTURE). First it touches on the basic conceptual framework. "It is necessary to have a reasonably well-detailed, large scale map for conducting adventures outdoors." So this makes it clear that Outdoor adventures are a distinct type, but that they follow the 'map and key' framework also used in dungeons. It then goes on to describe them as a follow on to "those in the small community and nearby underground maze." So in this first paragraph we have the basic schema of how this fits into the game and the world described.
Next it describes world maps, which we are told should be a first priority and will have a scale of 20 to 40 miles per hexagon. It then describes 'smaller scale maps' as having 5 hexagons per large scale map hexagon, and describes how the two sizes would be arranged. It is then explained that there are FOUR subcategories of outdoor adventure, land adventures, adventures in the air, waterborne adventures, and underwater adventures. Presumably each of these shares the above considerations about mapping, though it says underwater is more dungeonlike in practice. I guess you could hexcrawl across the ocean however as far as the DMG is concerned (either on and/or below the surface)! lol.
From here we get the LAND ADVENTURES section, which covers a whole slew of topics. First we learn that the map needs to note population density, or at least give a general idea of it. Then we dive into 'Chance of Encounter', which tells us, for each type of terrain (plain, scrub, forest, desert, hills, mountains, and marsh) how often to roll for encounters, and for each density (relatively dense, moderate to sparse/patrolled, and uninhabited/wilderness) what the base chance is. From here we go into detailed procedures for how an encounter happens, encounter distance, what a confrontation (distance under 1") means, etc. Next we get a section on movement that basically just adds a rule for very large groups to the PHB rules. Then we have the 'Becoming Lost' topic, which contains a fairly elaborate procedure for determining if, when, and the effects of, getting lost. We also get a note that if you follow a 'proper map' you won't get lost (I assume this means the heavily annotated type normally produced by adventuring groups, not a treasure map). Rest and Forced Movement round out this section.
I won't go into the other types of outdoor adventures except to note they include VERY extensive rules for flying, watercraft (including an entire wargame of small ship combat), etc. Suffice it to say you should be well equipped to handle most situations! There are even rules covering most of the common spells and their off-label uses in these various types of adventure.
FInally there is an entire subchapter titled 'OUTDOOR MOVEMENT', which elaborates on and to a degree rewrites the PHB movement rules. It includes the uses of mounts, effects of terrain on movement, use of watercraft, and some other details.
So, the one thing we are missing here is anything talking about encounter tables. We know how to discover IF an encounter happened, and what to do about it, but we have no rosters of bad guys, or even a rule on how to structure a table, what sort of things should go on it, etc. But first we have a slight diversion:
Appendix B: RANDOM WILDERNESS TERRAIN - this is exactly what the label says on the tin. It includes an Inhabitation Table, used to determine what sort, if any, civilization exists in a hexagon when it is entered, noting that 1 out of 100 hexes will have a city of up to 60,000 population!!!! So, maybe its not quite wilderness after all, lol. Presumably this is all assumed to fall under the rubric that the DM will filter the results!
And now we have APPENDIX C: RANDOM MONSTER ENCOUNTERS - this details encounters for all types of terrain, dungeons, underwater, etc. and is QUITE extensive, including rules for NPC parties, patrols, generation of fortifications, covering various climates and degrees of inhabitation, etc. It also includes a CITY/TOWN encounters section. Lets just say that the rules are QUITE extensive and cover 20 pages of dense text and tables!
Appendix O recapitulates and expands on the encumbrance of various items. Appendix P covers building NPC parties (well, it talks about PCs, but its main use seems more like building full up NPC groups to run into in... THE WILDERNESS!)

Obviously AD&D also contains an entire BOOK, the Wilderness Survival Guide, which greatly expands on all of the above information, and comes in at a hefty 150 pages or more. I know it contains the 2nd (or maybe 3rd) iteration of the NWP skill system, but I really didn't read it much.
So, if we follow the rules in this book, then parties of some level, presumably at least 3rd-5th, can venture out into the wilds, and either experience a randomly generated or a fully mapped, hexcrawl. The rules above will provide for how the party moves, navigates, what it eats and drinks, what it can carry, and the sorts of things it will encounter. There's not a LOT on how to draw maps, nothing much about symbols and whatnot, but presumably all of this should be fairly self-evident and follow from the necessity to depict all of the stuff detailed above. Obviously the DM is encouraged to include fantastical elements, their own 'keyed' encounters (which are stated to displace any random ones) etc. This seems to be a complete system!
I'd observe that when you actually USE it, its hard to carry enough food, water, weapons, armor, and other equipment, and you have to make hard trade-offs between movement speed and being maximally well-equipped. There is also the disease rule, which adds another almost TB2 grind-like factor. Spell casting is well considered too, as the PCs will lack a ready supply of ingredients for many spells, books are fairly heavy and easily damaged, etc. You can only memorize a specific number of spell levels per rest too! Bunkering down in a camp is possible, but will eat up rations and subject the party to random encounters (which happen even if you sit still).
I really don't have time to cover the 5e equivalent right now, and this post is quite long, so I will look at that and contrast them in detail later.