Fly UAV autonomously in indoor without SLAM ROS/Gazebo

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Hello, So I'm planning to fly ErleCopter UAV in indoor environment there are two main things that I have to do: 1- takeoff and land Autonomously ( I already done that with ROS node ) 2- fly the UAV in a path inside a room ( I have to load the map of the room and fly the UAV in a predefined path) I'll just let the UAV fly in the room and collect some data using external sensors.

My questions is: from where can I start, if I want to load the map in Gazebo and fly the UAV in a predefined path using ROS
Im using ROS indigo and Gazebo 4 simulator.