Well, obviously not all towns have railroad tracks, but if they do then the locals will always be happy point you in the right direction. Usually you can follow the tracks for a mile or two and eventually arrive to some nice bushes or a concealed spot. I prefer it to next to the highway because less trains pass by each night than cars on the highway.
Be wary with frieght hopping; it's not for the faint of heart. I've only done it once, and it was in Peru, so I don't know much about the railways in the U.S. You can find a local, experienced rail hopper near you, and he'll give you the run down on the trains in the area.
[i:24f401f973]p.s. while I'm glad to alleviate some of your fears, be sure to never let your guard down. I don't know if you've hitched before or travelled this way in the past, but you should always watch your back. 99% of the time nothing will happen, but I don't want to give you the idea that it's happy-go-lucky all the time. You'll have a great time, just keep your eyes peeled, and enjoy yourself!