WOW? World of Warcraft? This kind of game takes significant bandwidth, I believe. Most campgrounds have limited backhaul (connection to internet). They frown on movie downloads and serious gaming as it leaves little room for other users on the network. You need to check with the campgrounds you are going to to see what they offer in terms of connectivity.
We use MiFi with 5 Gb, but don't do movies or gaming. We use 3 to 4 Gb each month when we are on the road long term. As always YMMV (I see you are new, YMMV = Your Mileage May Vary)