implementing a wall following robot in ros

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Hi all,

I have a mobile robot and I would like it to follow a wall of a room. I already have a map of the room. I am using Wheel encoders for odometry. I am fusing data from wheel encoders and IMU using robot_pose_ekf. I have a Hokuyo lidar for localization and obstacle avoidance. I am also using Kinect to see obstacles which can not be seen by the hokuyo. I am using amcl for localization. I have couple of sharp sensors on the side for wall following. Now, I would like to know what is the best technique for wall following? Couple of techniques which I can think of:
1. Use the map to come up with an initial global plan and then follow that global plan and change it if you see an obstacle which is not in the map.
2. Dont use any global plan. Just follow the wall using the data from the sensors. This might be more difficult given that there can be wide variety of obstacles close to the wall and making sure that staying at a fixed distance from them might be tricky.

My one constraint is that I want the robot to be always at a fixed distance of 2 inches approx. from the wall (or an obstacle close to the wall).

I know this is a very general question but any suggestions regarding it will be appreciated. Please let me know if you need more information from me.

Thanks in advance.
Naman Kumar