If so how would be the best way of strapping it down.
Mattress and box spring on top of car.
You can use a plastic mattress cover to prevent your mattress from collecting dirt and permanent stains.
While driving with a mattress on top of your vehicle it is a good idea to stick to the back roads and stay off of busy streets just in case something happens.
There should be enough to secure one end under the front of your car and enough at the other end to secure the second end under the back of your car.
Put a piece of rope on the roof of the car that goes from back bumper to front bumper.
Put the mattress on top of the car and rope so that it goes length wise with the length of the car see pics above.
Do you think it is safe and or possible to move a queen size mattress on top of it.
Secure your mattress to the top of the car.
In addition keep an eye on the mattress so you notice if it starts to slip a rope comes loose or the plastic breaks.
During the process of being moved the sides and top of your mattress may come in contact with floors stairs the ground outside and the inside of a moving van or the top of your car.
Toss the first long piece of rope over the length of the mattress.
Place the mattress on the roof making sure it s in the middle.
Buy sturdy rope nylon or polyester based.