What are you running for air pressure in the front & rear tires? Are the tires load Range E? F? G? A tire with a firm sidewall makes a big difference in side to side sway. As others have said, some of it is a learning experience, especially when entering and leaving parking lots. You generally want to do it as square as possible, if you are at an angle one of the front tires will go over any dip or bump first, starting the camper rocking, then when the rear tire go through it one at a time, it really gets to rock & rolling.
Scott