@Beoric : I don't understand this sentence
You can't just make the terrain features less granular you increase the scale or terrain descriptions lose a lot of meaning, when there is one or two days travel between them.
In general, I understand your longing for a more accurate outdoor travel simulation, but if I were to channel my inner
@EOTB, I think he would say something like,
"Is this something you think your players would enjoy?". The 6-mile terrain hexes themselves are intended to serve the purpose of "easy route" vs. "hard". It seems like, you are just seeking a finer resolution.
Well, looking at the L1 map, forests are generally 3-6 hexes wide, and there can be 5-10 hexes between terrain features in the grasslands. If you are using 6 mile hexes, this likely means you are experiencing a change in terrain 0-1 times per day, and that is assuming you are travelling for 8 hours a day unencumbered.
If you look at Two orcs' map and treat it as though hexes were six miles, each mountain hex could contain 1-6 more or less parallel mountain ridges, depending on the width of the ridge, with valleys between them. So it is not a simple as saying a mountain icon in a 1 mile hex means "mountain", and a mountain icon in a 6 mile hex means "mountain", and a mountain icon in a 24-30 mile hex means "mountain".
Travelling in larger hexes means you are handwaiving many travel choices made within them, which requires a different kind of narration. It also implies that when you put an obstacle in their path using a larger scale, it should probably be a bigger obstacle, since the ones you are handwaiving aren't worth playing. I an thinking this through as I write, but that seems to follow for me. When you change the scale, you change the narration, and you change the nature of the obstacles.
And for that matter, you change the resource management game. Water is a daily resource, you don't track it if travel is measured in hours, you do track it if travel is measured in days, and you have to find a way of handwaiving it if travel is measured in weeks (because characters can die of thirst between decision points).
I generally take the x2 travel time through mountainous terrain to be because of the winding paths you're forced to take rather than a slower pace. Through my own travels I find decision points to be things like trying to ford a river vs. looking for a better ford, regaining your bearing by scaling a hill vs. pushing on, backtracking when you're lost vs. aiming for a catching feature (like a stream or powerline) and most importantly if you find a good spot to camp early, do you push on hoping there is another further ahead. Being hounded by monsters would make the decisions more poignant but not much different.
I think the only way to truly simlate this would be to not use hexes at all and only feed players information verbally, to let them draw their own maps. Tricky travel decisions would be more like encounters than ongoing challenges. Hexes warp the players' understanding of space, just like characters swell to become 5' wide on 5' grids they imagine that entering a hex means their physical presence covers all of it.
Travel in the trackless mountains would be at half speed only if you don't take into account the fact that you are rarely able to move directly toward your destination. You may have to go 20 or 50 miles out of your way to get around a 2 mile wide mountain ridge, or consider scaling the mountain instead. If you don't simulate that with forced direction changes on your map, you need to seriously cut travel speeds. So again, when you move to a larger hex map you need to change the impact of a hex on travel, because of all of the obstacles that are being handwaived.
The hexes aren't for the players, they are really a guide for me. I would rather find a way to remove the hexes from the player's map. And yes, major travel decisions are encounters.