Ah this is so cool! Great job on this map.
It reminds me of a huge map I drew a couple years ago. It was about 16 sheets of graph paper taped together at the seams.. Of an 'undermountain' type terrain. The entrance was a Goblin horde's cave which led to a giant expanse of caverns inside a dead volcano. I believe there was also a Dwarven hold and deeper down there were vast fields of fungi and an area of nothing but crystal deposits everywhere. brings back memories..
Damn I think I'd like to do that again!