I would just like to point out the obvious, if this deal gonna go bad due to a CI, it'll happen during the pick up. After that he's just gotta not make mistakes. No speeding, no falling as sleep at the wheel all the stuff you already know.
Just make sure to plan for a flat tire. It happens regardless of how new everything is. Shit does happen. Hopefully he buys a newer full size pick up with a tanoe cover. Usually the spare is underneath the bed. A good truck will make through the mountains and can handle pretty much all weather conditions. If I had to choose it would be a new Suburban LTZ with 4x4, they look dope, extremely comfortable traveling such a long distance. Massive "covered" storage space. If he does get pulled over and questioned, he can tell part of the truth. Ya flew to California because I got a steal of deal on this and wanted to drive it back himself. People do this all the time. I'm assuming he wont be able to get proper tags until he gets back to home.
Make sure he doens't buy an H2, or a PT cruiser. Those known trafficking vehicles.
I'm just throwing ideas, to help make sure everything was thought of. Brain storming if you will.
Since you said there is still some weeks to come before this happens this will give me chance to holler at my mexican homies that do this on the regular.
Do you know if by chance the weed isn't fully cured? That would be your best bet, you can squeeze "damp" weed in vaccuumed sealed bags pretty tight and it'll puff back up when you cut one side of the bag and wait a couple days. I guess it really doesn't matter as far as the cure, just make sure it has plenty of moisture.
I'm sure you know some of this stuff already, it's just a brain storming sesh.
I really with this was cocaine. It would open up soooo many different options.
For the LSD you could do what the fella's around here do for x pills. Put in smaller vials and mold candle wax around the container. Of course they just mail the candles.