So Dungeon World. It's a lot of fun. Basically if you can have a conversation with another person you can play. Right now our two heroes fled the undead infested, ruined city for the relative safety of town. Our game starts in 1.5 hours!
Play flows nicely back and forth between me and the other players. This is good. Sometimes we don't fill out the fiction as much as we should and jump straight into the mechanics. Gotta slow down a little here. It's cool watching the world unfold as we play. I didn't have a particular map in mind. As I ask questions and the players Spout Lore and Discern Realities we add stuff to the map and the fictional space.
Transition from Moldvay:
It's very smooth but DW Principles for the GM to follow conflict with Moldvay's Principles. Several things drop out fast. You lose the mapper and caller. There isn't a real need to map in DW. I think you could arrange it so this matters. I am slowly hacking together a DW-hack based on Moldvay. I want to see if this actually works without messing up the Flow.
In some ways Burning Wheel and Dungeon World share similar design philosophers with regards to dungeons. Get to the interesting stuff, skip the mapping.
I invoked a Moldvay Principle of relating information about the world and dungeons impartially (sometimes Drugar makes me laugh, with the bad dice rolls and all).
Sage did the Principles of Moldvay here:http://www.latorra.org/2010/09/28/the-principles-of-moldvay-dd/
So I am going to use those as a starting point for hacking.