Places that don’t allow privately owned weapons on their property should have a guard shack at the entrance where you can check your gun in a secured safe when you drive onto the property.
BAE Systems here does, and will secure firearms for visitors. I have a couple shooter friends who work there and when I stop by for a lunch in the exec cafeteria, or just a visit, the gate keeper is happy to oblige my Kimber.
http://www.baesystems.com/what-we-do-rus?_afrLoop=322534232025000&_afrWindowMode=0&_afrWindowId=null
Same with a VP I know at Gichner Shelter Systems, in Dallastown. The gatekeeper will secure firearms.
Watching the Giants v Cowboys while listening to GT, I just checked the local weather, and they’re forecasting 3-6” of snow for all day Wednesday. Swell!