A little extra sleeping room in your RV might be nice, but make sure this is realistic before upgrading to a king-size bed. Because RV space is limited, a larger bed may not fit at all or at least seriously impede walking space. Thus, compare your RV interior to the mattress size and consider the pros of having extra leg room at night compared to less space during the day. If you have plenty of room in your RV, you may wish to upgrade to a king for more luxurious sleeping.
Measure the width and length of a king-size mattress in your RV bedroom. Make a little mark on the floor with chalk to record the dimensions. RV mattress sizes can vary by manufacturer, but are usually 72 inches by 80 inches, though some RV mattresses equal the dimensions of standard home king-size mattresses at 76 inches by 80 inches.
Make an outline of the king-size mattress using a piece of yarn. Lay the yarn on the floor, using your chalk marks as guides.
Walk around the yarn to determine if a king-size bed would leave enough room for you to move around your bedroom.
Measure the main entrance door and the bedroom door in your RV to find out if a king-size mattress will fit through the openings.
Check if your current bed frame will accommodate a king-size mattress. If the built-in RV queen bed frame is just a flat board, it is typically okay to place a king-size mattress on it and let it overhang. If the built-in frame has vertical side walls, you will need to build a new bed frame or hire a carpenter.
Purchase an RV king mattress or a standard home king mattress, depending on the space in your RV. Standard home mattresses are cheaper, but usually larger. If your RV can accommodate the larger size of a home king mattress, you can save some money. If space is limited, buy an RV king mattress. Check the dimensions of the mattress before you buy, since sizes can vary by manufacturer.
Carry the queen-size mattress out of your RV and bring in the king size. Lay the new king mattress on your bed frame.