The couple places where you are suppose to be able to get up onto the rocks have stairways leading up. If you are in the right area and click on top of the rock your character should find the way up.
There are other places you can toss a teleporter stone onto the mountain top (etc), but you have to play around with where your character is standing and where you are trying to drop the stone to get something that works. for example, see;
a way out, if you're Stuck in the Easter Egg Area (broken links are fixed in a reply)
To clear as much fog-of-war as possible, try a combination of;
- Max Elven Sight (much more effective) and Ranger Sight (if you have the skill points to spare and really want to maximize your sight range).
- Keep any equipment you find with sight bonuses, to use when exploring.
- Toss a teleporter stone onto/into inaccessible regions and move around by repeatedly tossing one stone and teleporting to it, as Alrik described (you are not suppose to be up on most mountains, across the river in the south east corner of the dark forest, etc, and will not be able to walk there).
- Cast Wizard's Sight twice in the same location (cast it a second time before the fog-of-war fills in again from the first, and it will remain clear). Hold the shift key down to move the screen focus away from your character and towards the area you want to clear.
Testing weapon range, I once used
DAD's item editor to put a +1000 (IIRC) sight bonus on a ring, which cleared the fog of war for most of the wastelands. Adding the same sight bonus to another ring, the game crashed when I tried to equip it.
