"I am not bound by the Constitution to honor your Second Amendment rights on my property."
No, you aren't, in you private home.
If you have a business parking-lot open to the public, then, yes you are.
If you own a business parking lot, you have every right to fence it in, and require EVERY car that enters to be searched before entry.
Your company would turn to crap, and go out of business, but does anyone really care?
It's still my parking lot, and I still set rules for access.
I can limit the amount of time you can have your car parked there, I can limit the type of vehicles parked (NO TRUCKS, NO BUSES), I can limit what times and what days you may enter.
I can set all sorts of limits to your use of my parking lot.