Note: This needs references to the relevant stories, etc.
There is a Campus Map.
The cottages radiate outwards from the center on three axes. Dickinson is about 400 yards northeast of the campus on Dickinson Hill; Whitman is about 300 yards beyond it, below the hill. These two are girls' cottages.
Melville, Emerson and Dickinson are for "pretties", that is, students who look entirely (or almost) human. Whitman and Twain are mixed GSD and normal looking students. Poe is mostly normal looking students with several students having mild GSD mixed in. Hawthorne is for students who need medical support or who pose a danger to themselves or others.
Cottages are about 80 feet long, 46 feet wide and 56 (?) feet high, Melville and Hawthorne being the exceptions. The first floor (American numbering, ground floor for Europeans) is given to the entrance, a sitting and lounging room, the house mother's apartment, a library and other facilities.
Note that there is a second description in a later story that makes the rooms 20' x 12. This obviously affects the outside dimensions as well.
Floors 2 through 4 have eight 10 x 10 rooms running the entire length of each long wall. One end has a combined sunroom, study room, balcony (?) and TV room which seems to be 26 feet wide and 7 feet deep. (If it was any deeper the last two student rooms wouldn't have doors, if it was narrower Phase wouldn't be able to be half through the wall while studying.) There is a stairwell on the other end. Bathrooms, showers and utility closets are in the center. There's also at least one elevator, possibly both a passenger and freight elevator. There's no indication whether that's on the end with the stairwell or in the center.
This arrangement means that the corridor is rectangular; the rooms in the middle can't see across to the corresponding room because the utility core is in the way.
Room numbering appears to start with x01 next to the sunroom and going up to x08 on one wall, and then continuing with x09 through x16 on the other wall, ending with x16 next to the sunroom. The sunroom is usually oriented toward the west (this may be wrong, though). Notice that this numbering scheme is dictated by the room assignments for Team Kimba.
The fifth floor has four very large dormer rooms and other goodies, some of which are legacies of previous generations of students. Since this is in New England a flat roof is not possible - heavy snowstorms would pose too much of a danger of the roof collapsing. However, the fight with the Ninjas in Reflections in an Evil Eye implies that the roof is flat. There are occasional comments and scenes elsewhere that imply the same thing. Ayla calls it a mansard style roof.
The basement has the laundry room, storage areas and several other function areas. In Poe cottage, for example, the basement has an exercise room and the Lovecraft Room. Or at least the door to the Lovecraft room. When it isn't elsewhere.
Room arrangements seem to be somewhat flexible. The original stories imply that each room has two beds, two desks, one or two standing bureau and dresser sets, and a student dorm fridge. How all of this will fit is somewhat problematic. Suggestions are welcome.
Freshmen are usually on the second floor with a few sophomores. Sophomores and Juniors are on the third floor, Juniors and Seniors on the fourth floor, and seniors with a lot of clout are in the dormer rooms. Most rooms are doubles; the administration actively discourages singles except for dire necessity. Thus the capacity of each of the standard cottages is 104 students. Melville can hold 150 and Hawthorne is (almost) all singles, so it can only hold around 85.
Three of the cottages, Hawthorne, Twain and Whitman, have underground tunnels to the campus' tunnel system. A spur from Poe to the Hawthorne tunnel was added in Winter 2006 term after Halloween. There's also a direct tunnel from Hawthorne to the Doyle Medical Complex (the campus hospital). The reason for the first three tunnels is so that students with severe GSD can go from their cottages to class underground on Red and Yellow or Amber flag days. Not a very pretty reason, but then the world isn't always the way we'd like it to be. Since the spur from Poe seems to have been funded by Gabriella Guzman, it's most likely to allow Jamie Carson to use it while she's not particularly human looking. Whether the Administration is going to start moving students with more severe GSD into Poe isn't, at present, known.