Car Donations in California

I own a home that is about one mile away from the home that I currently live in. It’s being used for storage and has quite a but of stuff in and around is as it has been almost constantly lived in for over 200 years! My problem is that over the past year, we have had stuff stolen five times. That last time being today. They have taken an old car that I was going to donate to the Kidney Foundation, among about 3,000 dollars worth of other things. I don’t have the time to be there, or to drive by all the time and don’t have money for a proper security system. Plus all of the stuff that has been stolen has been from outside/under barn/etc. Has anyone found a solution to a similar problem? The police don’t do anything so we’ve stopped notifying them. Any suggestions are greatly appreciated!!
thanks for the advice! we have up three no tresspassing signs already. they are very visable so they know that it’s not for the taking.
hey MOFO, i’m not a hoarder! i have things. like furniture that’s relatively new, my grandmother’s china, artwork, family heirlooms that i don’t have room for. sorry you don’t have such things but some do. and i didn’t buy the house to store things–i inherited it. mofo.