Mouselook/Freelook?

I’m trying to instead of creating individual models, create entire levels for the Blender game engine. Unfortunately the default perspective and orthopedic views don’t allow much room for navigation of the scale needed to span across a level. Besides using the Blender game-engine, is there anyway I can navigate the level using a mouselook/freelook type of movement, or is using python scripts with the game-engine my only option?

3d viewport press: Shift+F followed by Tab to turn on gravity. WASD to move around. Rest of the controls are listed along the bottom of the viewport.