You want a Repeater/amplifier
Not a wifi router
You want to increase the signal going each way
A Repeater does not 'connect'/talk to the campground wifi access point, it just increases the signal level, communication is handled by your pc/ device's
There are routers, repeaters, and Bridges
If you use a router you must input wifi password data for the campground into router if it is going to be connecting to the wifi, then you have a different password access for your router
I'm not an expert on this, but i have used wifi repeaters and have an old one stored under the bed