From the OR State Parks site “ Can I have mail delivered to my camp site? We ask that you refrain to having mail delivered to camp sites due to the diffculty to getting mail to the recipient or having to try to forward mail if you have departed.”. This was asked regarding another park, but I believe it is their general policy. I have not seen enough staff at any OSP to handle mail/packages.

We always do Amazon locker pick ups near campgrounds and that has worked great for us

I’m sorry I haven’t the slightest idea. You would need to ask the campground that question.

Suggest calling the park for an official answer