In terms of your question about storing the weapon in your vehicle, the CCW license, gives you privileges shown in bold print above. If you do not park your vehicle on company property, you would not need that privilege.175.60(15m) Employer restrictions.
(a) Except as provided in par. (b), an employer may prohibit a licensee or an out-of-state licensee that it employs from carrying a concealed weapon or a particular type of concealed weapon in the course of the licensee's or out-of-state licensee's employment or during any part of the licensee's or out-of-state licensee's course of employment.
(b) An employer may not prohibit a licensee or an out-of-state licensee, as a condition of employment, from carrying a concealed weapon, a particular type of concealed weapon, or ammunition or from storing a weapon, a particular type of weapon, or ammunition in the licensee's or out-of-state licensee's own motor vehicle, regardless of whether the motor vehicle is used in the course of employment or whether the motor vehicle is driven or parked on property used by the employer.
The trespass statute 943.13 establishes an exception to the firearms posting/notification prohibition, for parking areas on nonresidential grounds, or land owned by others, shown in bold, that is NOT dependent on having a CCW license.
943.13(1m)(c)2. While carrying a firearm, enters or remains in any part of a nonresidential building, grounds of a nonresidential building, or land that the actor does not own or occupy after the owner of the building, grounds, or land, if that part of the building, grounds, or land has not been leased to another person, or the occupant of that part of the building, grounds, or land has notified the actor not to enter or remain in that part of the building, grounds, or land while carrying a firearm or with that type of firearm. This subdivision does not apply to a part of a building, grounds, or land occupied by the state or by a local governmental unit, to a privately or publicly owned building on the grounds of a university or college, or to the grounds of or land owned or occupied by a university or college, or, if the firearm is in a vehicle driven or parked in the parking facility, to any part of a building, grounds, or land used as a parking facility.