Like I said, there is no moveable camera for objects in the ORTHO queue, so no need to change anything with regards to the camera. It's a special mode (mostly meant for GUI/HUD etc. elements) where the coordinates from your object are used as pixel coordinates (so it's also resolution dependant).
You can scroll pretty easily though. Just make a Node, attach all tiles to it, and move the Node left/right/up/down.
As an alternative, you could have a "normal" 3D scene, use the orthographic projection for the camera, and put your tiles on Quads facing the camera, and make sure the camera is at the right distance. This is escp. useful if you want to mix real 3D elements into your 2D scene.