One thing I know for sure about train hopping is that you sure as hell ain't living free when you're at risk of getting busted by the cops and facing a trespassing charge every moment that you're out there. There's a lot of legit reasons why people do it, but if your main goal is to feel free, I recommend getting a bike instead. You can go fast through remote areas with the wind in your hair, travel to wherever you like, sleep outdoors, and most of the time do not need to worry about drawing unwanted attention from law enforcement along the way. Good luck.