The thing about armor plate on a vehicle is it’s really heavy. The point of a vehicle is that it moves. Also, the engine, transmission, and suspension are all built for the specific weight of the vehicle, not a couple thousand pounds of steel. If you add the weight of armor, you have to upgrade everything, or modify it to go slower with the existing system, without flipping over or disabling itself. Top Gear, a car show in the UK, actually tried this with SUVs a couple years ago. It did not work well.
DIV Bond Car Pt. 1 video
3/8 inch steel plate weighs 15.32 pounds ref: http://www.turnersteelcoinc.com/html/plates.html A school bus is up to 46 feet long and 10 wide. If you ignore the roof but armor the floor and engine compartment, that’s around 46 long * 10 high * 3 sides + 10 * 10 * 2 (front and rear) = 1380 sq ft longways + 100 each front and rear ends = 1580 sq feet total, leaving the roof unarmored. At 15.32 lbs per square foot of 3/8 inch steel, that’s 24,205 pounds of steel.
That’s more than 12 tons. The bus itself weight between five and ten tons, depending on how it is made, so you’re looking at a vehicle weighing around 17 tons, before you put living quarters, water tanks, fuel, or sleeping accommodations inside, and it is now heavy enough to be of concern crossing certain bridges and overpasses and heavy enough to potentially cause landslides on unreinforced roads. Does any of that sound wise?
If you add lots of armor plate, you also change the point of balance, making the vehicle top heavy, so it has to go slower around corners. If you DO opt for heavy steel armor plate to cover a bus to its roof and underneath like an MRAP, that’s even worse.
Overweight vehicles are currently of interest to both the highway patrol and homeland security, both for taxes and potential threat, since they might be bombs rather than armor plate. While they won’t set off gamma ray detectors on the interstate system, thankfully, they will certainly require lots of stops at the commercial truck weigh stations, and they become interesting to the more paranoid law enforcement.
It is probably a better idea to have a conventional cheerful snow bird fiberglass RV that draws no attention, staying at the usual upscale RV parks and sporting the Good Sam equivalent bumper sticker broadcasting how harmless you are, possibly distracting with talk about how much fun it was to restore the RV from the rotting hulk it was when you bought it cheap at an estate sale auction. Look like a tourist couple, and hide a gun locker in the floor. An RV won’t draw attention and gets a free pass moving around, because you’re retired tourists seeing America, not hippie/trimmers carrying a hundred pounds of dope and begging for a DEA raid, which is what most people think when seeing a converted school bus. I’m just saying. Sincerely, – I.K.