I usually expose the moon using the "moony 11" rule and find that works--1/ISO at f:11. If you spot meter it, I would put it about 1-1/2 stops over middle grey for color slide film or 2 stops over for color print, and you could probably get away with another half stop for B&W neg, depending on what else is in the scene.
The hardest thing to do is to photograph by moonlight with the moon in the frame. An ND grad is usually not enough to bring it in line with the landscape. I've been thinking of making some sort of mask to double expose for that situation.