The Southern Tier route takes you on I-10 between Ehrenberg, AZ (just on the border of CA and AZ) and 12 miles past Quartzsite, AZ (you take local roads through Quartzsite). It is a total of 34 miles. The shoulders are wide and full of debris but the road is straight, relatively flat and time on the interstate is short.

Here is a zoomable map of the ACA Southern Tier Route: http://tsteven4.qwestoffice.net/maps...TierRoute.html

Ray