I would paint a view of the inside of the place, that way it would look like the door was open all the time :) Right!? Okay. How about a CADPAT camo pattern? On a serious side I'm really not too sure - perhaps more of a vintage type colour palate would suit the schoolhouse.
I like black especially if the trim is an ivory colour but I have always thought that a rich dark turquoise also was a nice colour for red brick trim, especially the old Ontario red brick.