All activities associated with the on-site retail sales of storage services, including the lease of fixed, individually secured and self-contained storage lockers or rooms, must occur within a permanent, approved and permitted enclosed structure on property owned, operated or otherwise legally controlled by the lessor of said retail storage services. Any incidental outdoor storage, such as parking for automobiles, trucks, buses, motorcycles, and highway and non-highway recreational vehicles, must be shown on the site plan, and it shall be screened with walls or fences as determined by the Planning Board.