No travel item is needed to visit Lava Craters, there are no quests.
Build the 3 pipelines needed to connect the Water Tower to the 3 craters to distinguish the flames there. If the pipeline is correct click the craters to extinguish the flames and turn them into piles of sulfur, when you take the sulfur home some will drop Lucky Coins
The land is rich in Sulfur, you will need all of this.
There are also underground resources of Iron and Basalt, use Compasses and Geologists to extract these. Do not leave any of these resources on the land, you will need them later.
Can be found on the land, take this home for visit interactions
Once the pipelines are finished and all the resources collected Lava Craters can be colonised.