Amazon Delivery Too Big?

I have what should be a super simple question. I just started living in my 25’ Jayco and I’m LOVING it! One issue I’m having is getting packages delivered.

The Colorado state park I’m in doesn’t allow direct package delivery to campsites, so I’m using an Amazon locker nearby. This is fine, but I need an item that Amazon has declared too large for an Amazon locker.

I don’t have a home address or friends nearby that I can use, and Amazon isn’t suggesting any alternatives. What do you other full-timers do in this situation?