Looks similar to A* to my non-Clojure using eye. How has your performance been? If I use a 1000 x 1000 grid in my A* Python implementation I wrote last night it takes forever.
To tell you the truth I didn't really know about this algorithm.
I just went at the problem function by function and this is what I ended up with.
My next idea is to "prerender" a series of interconnected waypoints across the map at the start and then pathfind to the nearest one before moving long distances using small bursts of pathfinding to move around obstacles and stay on track.