You're confused because it's confusing - and I'm a professional nerd.
And the ways to access cameras have been changing, so it's a moving target.
Think about it this way:
- you need to buy a camera that works on WiFi
- you need some sort of "Hot Spot" device. That's the way to connect "WiFi" stuff to the cellular network, so you can make things connect without relying on the campground WiFi
- and you'll need a smartphone
The less expensive cameras take a lot of effort (dynamic dns, punching holes in the firewall, port forwarding).
But the more expensive cameras, like Nest, for example make things a lot easier.
If you've got the budget, take a moment to read up about the Nest camera (not an endorsement, just a suggestion). Read their installation documentation and see it makes sense.