Filling in the Gaps WY, WA, TX

[HydrexRider]

I am currently setting up a route on garman mapsource for a ride from Brownsville TX to Bellingham WA. Im using the Tour of Idaho, and Shadow of the Rockies. However I do not have any routes for brownsville to el paso, the end of the shadow of the rockies to the begining of the Tour of Idaho, and the end of the Tour of Idaho to Bellingham. I was wondering if anyone could help me out in anyway by telling me some possible routes to use or any way points or gpx files that will help. I would really appreciate it.