RV WIFI

We work on the road living at rv parks. Rv Wi-Fi sucks! We bought the nighthawk r7000 and use it as an access point, connected straight into the rv park internet modem (parked right up against the utility pole ;) my question is what is a good setup? We run 2 Xbox One for gaming it is set to ipv4 I can't change that due to the parks modem I can't get into the setting to see if I can change that. I tried using as a router and I get a double nat issue. I have no clue what I'm doing. Ive read u habe to make sure the ap ip address is set to static but how do I do all this to ensure there is no interference. I am clueless! I wanna add, both Xbox play just fine every now n then one of us get booted or have Mic issues disconnecting. Nat setting on the Xbox is moderate I'd like to have that open but there isn't a way to change anything.