Fire roads the whole way, parallel to the highway (on either side of the 95).
It's tough to find single track as the Rhino guys just widen it out.
There is a dragstrip of old highway just above the new Love's station, it's pretty cool.
Once you cross the 40, the wash or the RR tracks take you directly to Topock.
Thanks, I'm one of those "Rhino guys" so a single track wouldn't work anyway. I was trying to find a trail that would kinda parallel the river instead of the highway. I have gone almost as far as the Sand Bar, beyond that I'm not sure if there are any trails that go through the gorge area, hard to tell on google earth.
When you cross over to the north side of the 40.................make sure you stay on the south side of the rail road tracks heading towards Topock. If you are on the north side of the RR tracks you will hit the Wildlife Refuge before you make it to Topock and that can be a big fine. Just parallel the tracks until you hit the dead mans curve in the road......................go Right under the RR tracks bridge and Topock will be around the corner on your left