Need help with overworld maps and outdoor battlemaps

So I'm running lost mines and  just wondering when they are on over world map how should i work vision? do they see the entire map or do i fog of war an estimate of how far they can see and only uncover it a bit at a time? I use dynamic lighting so indoor battle maps and caves and such work fine for vision, but how do I go about outside things like a random encounter in the woods at day. Do they see the entire map or do i have to use dynamic lighting field of view and increase it for all the tokens so they can see a bit more then the normal site ranges in the dark? I hope you can understand what i mean sorry i'm not the best at wording things :)  thank you

Is the party familiar with the area? Having traveled thru here in thier youth before becoming adventures. Open the fog up more if they have , little less if this is all new to them. As for a random encounter use a non-specific outdoor map for the encounter, when one happens move the players to that map when the encounter is over move them back to the world map.

On the world map, I would say turn on Fog Of War, and "Reveal" everything (the entire map).  Then use the Fog Of War tool to re-hide specific regions/towns or town-names that they don't know about.  Let them see the entire map as far as Oceans, shores, forests, mountains, major roads, and bigger cities that everyone knows about.  Just have little blocks of blacked-out hidden areas for specific destinations that they haven't been to, haven't heard of, haven't discovered yet. On the random-encounter map in the daytime, I recommend either: Disable Dynamic Lighting, or, Turn On Global Illumination (acts like sunlight). Both those settings are under the Page settings.  Either one will let the players see the entire random encounter map (which is usually just a fairly small section of woods or road, so just let them see the whole tactical map especially if it is daytime).

I have done an area map with specific features on the GM layer. When they are close enough to observe the thing, drop it to the map layer.

thank you all for your help :)