Adventure Mode, is pretty much a map that you can find somewhere in the /config file that you load unto blockland, it is a .bls and a .jpeg somewhere I shall not reveal unless everyone here is a golden premium member of Badspot's Trio (which you can play all of his games for just 10$ a month) and in the same location you find a System_Adventure.zip file. then you put the .bls into /blockland/saves/slate/ and then click on the adventure mode button that overlaps with RTB, so it might become hard to click, and then you can see how to go from there.
Also, you might say "OMG, why has no-one shared about this?" well if you ever gain the knowledge and you are not a premium member, then you become banned from all of badspot's games, and his entire forums too. Also this ban applies to anyone who had "Viewed" the thread/topic that this was shared on. I'm pretty scared right now, because I'm not sure I'm allowed to spoil this much.