Not starting, and not charging the battery
I see this was posted 2 years ago, and hopefully you have your truck running properly again, but for the benefit of anyone else who may have this problem as well, here are a few suggestions...
Apparently the starter, alternator and battery are all new, and were all tested to be good. I also see the truck won't start after running for a long period of time "til it cools down." I take it to mean that after the engine cools down it WILL restart. So the problem appears not to be a problem with the battery or the alternator, but may be something else entirely. There is no mention as to the status of the voltage gauge in the dash, as that would be an immediate heads-up as to a problem. If the voltage gauge is showing around 12 volts or less, then the alternator is not applying charge to the electrical system and may be in fact, faulty. If the vehicle has a voltage regulator separate from the alternator, (most have an internal regulator found inside the alternator), then the regulator may be bad and needing replacement. However, again there is no mention of this. If the voltage gauge is reading 14 volts or just over, then the alternator and regulator are operating normally and should be applying charge to the electrical system.
If it in fact will restart after a cool down period, then I would suspect something in the electrical system having to do with starting the vehicle is overheating or is getting overheated due to a missing heat shield and will not allow restart until the part cools back down.
If it will not restart without jump starting the vehicle, then there may be a loose wire or connector someplace in the wiring system. These kinds of issues can be very difficult to diagnose, and may require an experienced certified mechanic to find.
Good Luck.