I want to say the concealed carry law only applies to residents. Non residents can carry concealed if they have a valid permit.
As for loaded in the truck, go for it. When I am running the desert/coyote hunting I have my AR15 (short rifle) ready to roll wedged between the seats muzzle down.
Last winter a high school girl ran into the back of my truck infront of my house, when the officer got here I told him I have a Michigan concealed weapons permint, he asked if I had a gun on me, I didnt but told him there were several loaded in the truck. His response was "Son this is Wyoming everyone has a gun in thier truck and next time I see you, you better have your pistol on you or your getting a ticket"
Just dont shoot from the truck, leave beer bottles everywhere, or cross country to much and you will be fine.