The Wasteland is a single map space with no immediate neighbors. Reaching it requires either Dimension Travel to red, or carrying an orange cube in your main inventory and waiting a couple hundred turns.
There are only two interesting features of the wasteland - one randomly assigned artifact, and a volcano. About 100 turns after arriving, the volcano will erupt and slowly fill the zone with lava, eventually destroying the artifact.
Terraforming is an ideal way to make short work of the volcano, which can be found with a scroll of cartography. If you lack that power, bring a couple potions of speed and depredation to find the artifact as rapidly as possible.
Note that if you use the orange cube to get here, you may have problems leaving. You will need to use a different means of level teleportation.