Dragons - The quicker way to do this is going out the spawn room through the bottom exit. Also, make sure to try and get power as soon as possible. The first dragon will be in the courtyard, which you have to fill with zombie souls until it disappears. The next dragon is located in the building with stained glass and computers. The final dragon is located within the pyramid room.
Bow - once all dragons are gone, go back up from the pyramid room and one your way up the stairs the bow will be there.