That's an amazing video, Gelli! That trainrider guys is nuts! (was nuts, I should say) I was thinking of riding inside a train, myself. A slightly slower one. I wonder how you'd get a freight schedule, so you'd know where a freight train was headed?
I've hitch-hiked a couple times- it's not a bad way to get around. It's not as common in Canada as it used to be when I was a kid. My Dad always used to stop for hitch-hikers, and he sometimes invited them to sleep in our spare room. I don't think my Mom was too happy about that... But we met some interesting folks.
I wonder how you'd get a freight schedule, so you'd know where a freight train was headed?
Half the fun is not knowing where the heck you'll end up! Seriopusly though, in most places freight schedules are reasonably easy to get hold of (ask local enthusiast websites etc), as many of them are fairly regular. No idea how it is in North America, but but in Europe, well over half the freights are regular, on a daily/weekly/whatever schedule, and many of them are empty in one direction [car transports from a factory, for example, are rarely of many use to bring anything the other way due to the types of wagons]. Admittedly most of these are either sealed containers, liquid wagons or open wagoons (eg used for taking coal to power stations) so not that easy to jump, but a bit of research should give you some idea. There are, of course, huge numbers of random/irregaulr services, which are more likely to suit your needs/purpose, but short of knowing somebody in a marshalling yard/whatever, finding out exactly when they are going and where is tricky.
Hopping freight trains in the US is a Federal offense and if the rail company chooses to prosecute, it could be costly - including time spent in jail. Also, as some have mentioned, a majority of the old boxcars have been replaced with containers on flatbeds. A good portion of the remaining boxcars are used for hauling livestock.
Anyway, here are some links you may find of interest:
How To Hop A Freight Train
Freight Hopping, Aborted
Train hoppers' adventure ends in arrest
Hopping Freight Trains In America by Duffy Littlejohn
I've hopped a train for about a mile here in my hometown if that counts