I'm a map-junkie. I just love making maps, and some of the maps I've drawn for my games have been in use for nearly thirty years — like these ones, which I've been digitally enhancing in the last few years but are still essentially the same pen-and-ink maps I drew all those many years ago.
For all that, I've never really got into drawing small-scale wilderness maps until very recently.
I overlaid a hex-grid on my old world-maps, and thought I'd have a go at detailing the area the party are wombling about in right now — and found that there are lots of things that need names, and that I suck at making up names. This map (click on the image for a bigger, more detailed version) covers an area 25 miles from side to side, and the internal hexes are therefore five miles across. I could use the same template to zoom in on one of the 5-mile hexes, in which case the small hexes would be one mile each, and so forth. But in spite of my map-junkieness, the probability of that happening is slim.
The thing is, I don't actually make up much stuff before game-time; I just kind of fill it in as I go along. So while a map like this one is reasonably useful, letting me know how long it's going to take the party to get back to Rath Donnan from the middle of the Weeping Wood for example, a smaller scale map becomes less and less useful because the area has already been dealt with on the fly, and the chances are that the party will never come back to the same spot again so keeping a very detailed area map is mostly pointless. If they do go back, I have my (mostly incomprehensible) scribbled notes to rely on.
If they decided to set up house out in the wilderness (not very likely with this particular group of players), then and only then would I consider putting in the effort to map a 5-mile hex in any detail.
Maps like this one are really only for my own use, and in truth I could make do with something a lot sketchier (and it would be a lot less work too). But I like making and looking at fancy-looking maps, so that's what I make for myself. The players get much less gorgeous maps to work with, if they get a map at all.
Ideally, I prefer my players to make their overland maps in the same way they deal with dungeon maps. That is, they find somebody who knows (or purports to know) the area they're interested in, get him to describe it, and draw the map themselves from his description. Then, if they're interested, they can fill in lacunae from their own experience as they're travelling through the area. From time to time I do provide them with a pre-made map, but I never make any guarantees as to its accuracy or reliability.
I remember once seeing a medieval map of the world which bore almost no relation to actual geographic reality; it showed Jerusalem at the centre of a more or less circular disc with squiggly edges, with England shown as a slightly detached bit of the edge of the world. "Roads" between Jerusalem and other cities were just straight ruled lines. I think they might have had travel time marked in next to some of them.
I think that keeping the real maps out of the players' grubby mitts adds to the mystery and enjoyment of the game. There are few DMs who would consider giving their players a complete map of any dungeon they're about to go frolicking in, so why should overland maps be any different?