I have a quarter mile long gravel drive and the house is out of site behind a locked gate. I installed a 2'x2'x4' Knack type steel box in front of the gate. I dug a couple of 2' deep holes under the box and concreted in foundation studs for which i drilled holes in the bottom of the box. Once the nuts were on, I staked the threads so they couldn't easily be backed off. Initially I left a wheel type combo lock that a delivery person could put through a hasp to lock the box, but somehow the lock sprouted legs and disappeared. I replaced it with a hasp/lock combo, so the lock can't wander off, but it's keyed, not a spin combo. Works just as well. Most of the time drivers have no trouble dropping packages into the box, but some can't figure out how to lock the hasp, some don't even try. If I get more than one delivery per day, the second driver will usually drop the package behind the locked box. Sometimes they leave a note and deliver the next day. Used to have a driver that would call me when he was at the gate, but he didn't last very long.
I always stop deliveries when I go on vacation, as I have had problems with mail and packages being pilfered from both boxes. That said, I had to narrow the slot in the USPS approved mail box because I could reach in with my fingers and snag a letter. Now the carrier can't be bothered to make sure that the mail drops down behind the slot. So it all depends on the delivery person; some will use the security measures to make sure that the packages are safe, while others couldn't give a hoot. And no matter what you do, a determined thief will get your deliveries before you do.