Ship your bikes on Amtrack.  I have a friend who takes him, his wife, and and their goldwings from utah to southern california on Amtrack.  They ride up to washington then take the train back.

I think he said it was about 200 or 250 for each leg to ship the big bike, but I am not posative.  In most cases, the money saved in fuel by not having to take your thirsty tow rig and being able to drive a more economical car or flying can save the cost of shipping the quad.   Worth looking into...