Hi @MattinNC,
Sorry, no. The EAP225-OD doesn't have that function. It cannot act as a "client" (aka STA) on someone elses wireless network.
But the CPE series can. I'd recommend the new CPE710 ideally.
https://www.tp-link.com/us/business-networking/outdoor-radio/
https://www.amazon.com/TP-Link-Transmission-Wireless-Passive-CPE710/dp/B08D71HC9L/ref=sr_1_1?crid=3B3HE1JOATGUF&dchild=1&keywords=cpe710&qid=1606001304&sprefix=cpe710%2Caps%2C194&sr=8-1
BUT, this will not really re-broadcast the Wifi for use inside of your RV (due to the directional nature of it's antenna). Also because an RV is a metal box. You would need to run Ethernet from this (or the CPE210/510) back into your trailer to either a PC, switch, or an indoor AP -- like the EAP225V3.
But, before you invest, make sure the campground actually has good Wifi/Internet. Move close to their AP and test with your phone / laptop / etc.
Many of the campgrounds I've stayed at have terrible Wifi -- too many clients, slow/overloaded broadband connection, poor signal. In almost all cases I have to use cellular/hotspot/Jetpack.
-Jonathan