I am trying to create the illusion that I am traveling down a path at high speeds but in reverse using a background i've created in photoshop. The background is a dirt path with trees. Is there a way to have the background layers continuosly loop to give the appearance that the viewer is moving very fast away from the distance?
i don't know if i really undertand your problem, but i think you can sold it making a copy of your background layer, put the 2 layers of the background side by side, create a null object to manipulate de layers, make a keyframe in position of null to start position with the first layer at the center of the composition and a end position with the second layer at the center the composition, create a loop out expression in the position property of null object and enable motion blur if you want.
http://www.videocopilot.net have a tutorial that will show you the techniques you need. Its showing how to zoom out from a building to outer space looking back at the earth, but the techniques andrew uses can be adapted to do exactly what you want.
Video Editor/Audio Mixer/ Compositor/Motion GFX/Barista
Character Options Ltd