Expedition Everest will be located adjacent to the lake between Asia and Dinoland, and the mountain itself with be in the region of 1 acre in size, and 200ft high. (Note that the 1 acre size does not include walkways, queue buildings, portions of the ride etc)
The map below shows its approximate position. (Note that the scale and position is approximate only). The yellow line indicates the new bridge that will link the area near to Theater in the Wild to the new attraction. New walkways will also connect the ride area to Asia, essentially making a walk around the entire lake. The yellow circle is a rough guide to where the mountain will be located.