Treat it as if you were blocking up a mobile home. If you use concrete blocks ALWAYS place wood at the top of each block pier between the concrete and the steel frame to prevent the blocks from cracking. I can explain why, if you like. Place one set of blocks (piers) under each frame rail near the front and near the back of the unit, and about every six to eight feet along the length. Since the spring hanger locations are designed to support the unit while moving, they are an excellent location for blocking, but sometimes difficult to maneuver around, but make sure you have at least one pair of pier blocks in this location. If you do not support the unit evenly, the metal frame will take on a permanent "set" over a period of time, so leveling and proper spacing is important. You are wise to remove the weight from the tires, as they could develop a lump over time. Some support under the gooseneck is wise too.