The cornucopia at the courtyard would be perfect, its center of everything basically. People could run into the castle or head down the path to hagrids hut and the forbidden forest which is loaded with spiders but has teir 2's past the spiders.
People could rush to the dungeons class room and find bottles of potion that allow you to breath underwater which would allow them to go down into the great lake (4th movie) where there would be nice treasure at the bottom.
The quidditch pitch booths from each school would have hidden teir 1 chests.
Tons of hidden passages in the school, even a passage way that brings you all the way to hogsmeade and back (3rd movie)
I have to say whoever makes this map would be awesome and deserve VIP! I would try to make it myself, but I have no knowledge of how to make one.
There are tons of maps of Hogwarts already maybe one of the creators would allow MCSG to use it?
Someone would just have to add the Dome and chests.