We have a 2013 3582RL also. We've done a few mods such as adding more shelving in the cabinets and pantry around the frig and added some extra insulation above the storage space below the bedroom to keep the cold and the hot out of the area. We've also added disc brakes to the unit and it made a world's of difference. Hope you enjoy your unit as much as we enjoy ours.
Hi Kelly! Hope all is well with you and the family. I think the exact length of our units is 38 ft 6 inches but don't hold me to that. Whenever we are asked by a campground we always tell them 40 ft and that satisfies them so they know what type of lot to assign us. Take care and stay safe!