Current Employees/Residents: Pinkamena, PinkiusPiecus. DustyBristle, Comito
The main entrance, of course, opens up into the shop's main room, with various candies and baked goods. The counter is where whichever Pinkie that's tending the store typically hangs out behind. There's a set of double doors behind the counter that lead to the kitchen.
Up the stairs across from the kitchen entrance is Pinkie's room. A door on a raised floor with a large hole in the center also leads into her room from an outer balcony, seemingly made for pegasus ponies.
The other small set of stairs presumably leads to other back rooms, such as the bathroom and Mr. and Mrs. Cake's room.