The wife and I are moving out of Washington and down into Arizona. Going to rent a big Penske truck and haul my stuff down. Have a large collection of firearms and ammo, don't know the laws regarding  the transporting of firearms , ammo and reloading supplies Powder and primers.  Will be going through Oregon, Nevada, staying the hell out of California, to get there. Anything someone might suggest before I leave. Thanks fellas.

Disconnect the battery wherever you stay overnight so the truck can’t be stolen.

Stay at motels where the rooms have external entrances and back in the space by your room door.

If possible use a cable or something to secure you stuff inside the truck.

Buy your self a few seconds if someone tries to take your stuff.

Legally, load it up and haul, make sure you are in weight limits. Safety wise, separate powder and primers. Security wise, bury guns away from the doors to impede access by thieves. Don't advertise that you have any guns/ammo, make the first look inside the truck very apparent that this is a household move and any officer who wants to search better bring a crew. When I moved half way across the country the Penske 26' truck, towing my pickup, had to go across scales, because it might be used commercially. A truck driver friend told me to have my wife follow me through the scales with the mini van loaded with stuff. They would greenlight us  through every time because we would be too much trouble to inspect and "Ain't nobody got time for that shit" at a weigh station.

I moved from Maryland to E Wa in a huge Penske truck, then back a few years later. I bought a few cheap rugs & wrapped the long guns in them, then wrapped the handguns in t shirts & put them in drawers. I loaded that stuff first, with the drawers facing the front of the truck, against the front wall. That pretty much buried them all behind the rest of my crap. I never stopped at any weigh stations, just rolled past. They say you should, but I made it both ways with no problems. Unhooking the battery is a good idea, as stated above! Get a GOOD lock, not a cheap master lock. One of those round ones with the hidden hasp...harder to cut. And park the thing in the most ridiculous spot...right out front! Take the ticket if you have to...just keep it visible!

Edit...load a couch last...you can always sleep on it if you’re worried!

Is someone driving a chase/second vehicle? I'd put the guns in there.

Ammo - just bury it inside the truck under all your other crap. If you're like me, that's a lot of weight and could overload the smaller vehicle.  My ammo fort was 1300 lbs.

Frankly, I'm not sure I'd be able to sleep in a hotel while driving a rental truck.  Nothing, absolutely nothing, is more inviting to dirt bags than rental trucks in hotel parking lots.

If it was me, I would plan to drive it non stop, taking naps in truck stops as needed, sleeping in the cab.

Don't overthink it
 I've moved 5 times with large collections.  Drive with traffic and don't get pulled over.  Do the trip in one day if possible, otherwise keep the truck in a lit parking area by your room.

Welcome to Arizona.... where all guns and knives run freely!

Some states don't require you to stop at scales and none are ever open weekends anyway.

I just made the same trip from OR. It's hot here BTW. If you need someone to shoot with and miss the rain hit me up.

I  won't be staying in a motel. Will stop at rest stops for awhile till I am able to drive on. had the same thought about burying the guns and ammo toward the front on middle of the truck.
Thanks, I do appreciate the help guys, moving because I retired and am fed up with Washington politics and the LIBS. Heading for a free state. Will keep all your advise in the back of my mind. Thanks again

Mostly this!

I went through scales once with my dad. I broke down a couple hours from home and he came to pick me up. He brought his service truck and had to go through the scales bc it is a commercial truck with DOT numbers. They red lighted us into the inspection lane. Guy came out, asked what was up and we explained. He looked at me and asked if I was the actual owner of the car on the trailer. I said I was and he said "just go" as if we were being a bother to him.

Be careful in rest stops as well. Not always the safest place to be.

Have a friend help with the drive and do it non stop, then pay for a one way flight back for your friend.

We used to move multiple truckloads of classified airborne
equipment across the country every few years.
Falls Church, VA to Palmdale, CA in a single run.
The AF finally realized they would save a LOT of money by putting the stuff on a Cargo plane.
One large system with both ground and airborne and ground portions took 12 trucks.

Multiple crews on each truck (3 drivers) so we could drive it it without overnight stops.
Same with chase cars carrying extra people.
Need to guard that truck when stops for
bathroom and eating are required.
Need enough people to let some of them sleep.
And whomever guarded the trucks while everyone else ate had to order a meal and eat in the car.

I stayed at a motel first time I moved, I never slept, was up every time I heard someone in parking lot.

Other time I just stopped at staffed rest area, caught a few hours and hit the road.