I find that a scale of hexes
approximately 1/4 the size of the regional maps (what Legacy ITL calls "province" scale, is useful if you want to track travel movement accurately, even if your map is at that scale.
That's because at that scale, arranged
the way I do it, you get a hex for the center of each hex, and a hex for all the corners and hexsides, and a hex for the space between the centers and the hexlines/corners of the regional-scale hex.
And THAT, allows you to do things like:
* Keep track of where the party is after one day of travel in terrain that is at one hex per two days (e.g. mountains, swamp).
* Have easy ways to mark where the party is after a half-day or quarter-day of travel.
* Be able to have them drift off course by less than an entire regional map hex, and still accurately track where they are.
* Have clear ways to move the party north, south, east or west, or several other directions, even if that doesn't match your regional map's hex grain.