I’m currently running The Moon is a Mirror from Trilemma design, and having a great old time with it, but I’m adding some old-school hex crawl around the area. This uses the 2e standard of rolling 1d8+1d12 to generate an encounter. The advantage of this method is that it gives you a nicely centered distribution that allows you to put less common encounters on the outer edges (2-3, 19-20) and more common encounters in the center (9-13). There’s more detail in the 2d Dungeon Master’s Guide, but the basics are that you make a check several times per day (depending on terrain) by rolling a d10. Each terrain has a likelyhood of encounter, and if you roll below that number, you then roll on the encounter table for that terrain type to determine what the party encounters.
This is a bit convoluted, but the end result is that in the mountains, three times per day I roll a d10. If I get less than a 3, then I roll 1d8+1d12 and I’ve got a random encounter to run the players through.
Like all Random Encounter tables, I’m generally using these as “writing prompts” to come up with something interesting. For example, if I roll a result of “Dwarven Guards”, the encounter might just be a group of dwarves guarding a caravan, or it might be a dwarven outpost along the route, or it might be an all-dwarven adventuring party returning from a nearby dungeon, with loads of loot, and a corpse of their comrade.
Random Encounters are seeds for stories.