(I tried posting a few minutes ago but it didn't appear to work - said I wasn't logged in even thought I was, so I apologies if this is a duplicate. )
We moved from AZ to OR 2.5 years ago. Last March we bought a 1999 Collins short bus cut away (6 windows) and tore out all the interior down to the exterior shell, removed all the warning lights, stop sign, A L L labels, patched holes. We have not painted the bus yet.
Last month (October) we started the build and got the floor in as well as the walls up to the windows and the insulation above the windows. OR requires only a permanent sleeping area and food prep area. That's all. I think we can get something passable in within a couple of weeks. We should be able to tag and insure it in OR at that time.
Unexpectedly, we have to move back to AZ in February 2019 for a year or two. We've got two months.
We can't paint the bus here in OR because the rainy season has started (wildfire smoke ash prevented it in the summer) and we do not have access to an enclosed space. We can tag and insure it in OR before the drive to AZ. We would be driving through either CA or NV to get to AZ. We've dug around and found some saying that CA is not cool with a privately owned bus that is still yellow. Is that true? Does anyone know about NV?
I'm thinking we can keep it registered as an OR RV for a while until we meet AZ requirements? Does AZ have a problem with a yellow bus even though all the markings of a school bus have been removed?
Our plan is to snowbird in the bus between AZ and OR with the bus as our home. There is a mail forwarding service in OR so if necessary we can keep an OR address. Not sure if that in necessary though.
As long as it is not a "California" bus...you should be OK passing through. They cannot enforce their wonky, liberal BS on out of state vehicles unless you want to move there and register it there.