Full sized should fit inside the ody with the rear seats removed. Queen, sadly needs to be tied down. Reccomend getting a set of bungee cables and cargo straps if you plan to carry on top. Use the cargo straps going across the width of the van and use the bungee going from the ends of the cargo rack over the end of the bed and connected to the cargo strap. this keeps the front end from floping all over the place.