There is a closed existing topic w/ the same title.
Anyway... i'm having the same problem:
After placing the gold bars I went to ATP to find Caesier stash but it's not were the guide and sahafiec videos show.
So far in my PDA there are:
24 ZEP confidential releases
20 collector entries
3 Important notes about Caesier treasures.
Is something missing !?
Also ... the mushroom reads NW and the guide/video show a NE location.
The other truck I found was in the old loner camp I defended earlier in the game, now deserted and nothing in the surrounding trees.