I presume you are already aquatinted with the actual stitching of the pics together? And it goes without saying that you will need a steady tripod.
First thing you need to work out is how long you would like the finished video to last and with what sort of frame rate. So if you want say 10 frames per second and you want it to last for 60 seconds, you're going to need to take 600 shots in that 4 hour period. That works out at 1 shot for every 24 seconds so this is what you would program in on your interval shooting mode.
In terms of other settings. Set your focus point and switch your camera to manual focus so it will not alter. Take some test shots in the dark first to make sure you're happy. Bear in mind that in my example, you're not going to have time to expose for more than 12 seconds or so (once you factor in buffering time) before the camera wants to take the next shot. I would be inclined to shoot in aperture priority mode and find an aperture and iso setting that work fine in the dark. That way you know that camera will be able to work the lighter it gets.
