Hi,
Everyone in the campground shares a rather narrow pipe. You can boost the signal--but the speed may remain quite dismal. Maybe email will work.
Back in the day, I used an Alpha Pro with a 40 db gain antenna. It would allow me to connect up to about 1/2 mile from a good source--so I'd use McDonald's and the like.
I do not recommend getting such a device. Cell phones are far better wobbly wide web suppliers.
Here is a link:
https://www.amazon.com/Alfa-Range-Repeater-Tube-AOA-2409-TF-Ant/dp/B07JBBCDD2