It is possible the first and second level are not originally part of Dwarf Home, but were added to it later on.
The square area of level 2 is: 1440 feet by 1260 feet = 1,814,400 square feet. Thats the size of outermost wall ( east-west ) to outermost wall ( north-south ) of the level.
all maps done; 42 maps, 320 rooms, 136 bad monsters, 20 good guys, 70 traps, 119 treasures.
Unless otherwise noted, the corridors are 15 feet high.