+Joe Johnston released How to Hexcrawl: a nice little pay-what-you-want primer on running a hex crawl in Labyrinth Lord, or any other D&D-like, gathering together the rules and charts you might use as well as some advice.
What I want to talk about, though is how to handle checking for encounters. Joe correctly points out (p 20) there’s a contradiction in the rules, or at least some confusion, about the step-by-step procedure of rolling once per day’s travel vs what happens when you travel over multiple terrain types and the admonition against checking more than 3-4 Times per day. He suggests 3 possibilities: roll based on the start hex, the last hex, or each time the terrain changes. Unfortunately those all skew the encounters one way or another.
I’d like to offer a fourth option:
4) Secretly roll 1d12 for the hour and 1 die of any type (or flip a coin) for day/night. At the appointed hour in the game day, roll for an encounter based on the current hex’s chance of encounter. This prorates the chances exactly. The only minor drawback, if it is a drawback, is you do need to pay slightly closer attention to what the in-game time is, though that shouldn’t be at all difficult since you already are dealing with the travel speed to traverse the hex.
N.B. How to Hexcrawl doesn’t mention it, but the assumed overland travel rate for most D&D editions is about 3 m.p.h. for unencumbered travelers, with an 8-hour effective travel day, which gets you the list 24 miles/day. With 6-mile hexes, each hex of travel is 2 hours. If you get in the habit of announcing the time of day as the party enters the hex (“it’s about 10 am when you get to the mountains”) it’s dead easy to tell if it’s time to roll for an encounter, and helps give the players a better sense of the passage of time anyway. This suggests a nice variation, if you want to roll for travel encounters and then separately for night encounters while camped: roll a d8 to see which hour of travel the encounter gets checked and then again at night based on the terrain where they are camped. Ideally you want to have a separate table, or at least adjust the results, for night encounters, since a caravan or troop of men are not at all likely to be traipsing through the woods in the dark.