We've stayed in a lot of campgrounds over the year, and I'd say roughly 20% of them have dependable wifi. Perhaps that's due to low power output on their antennas, and weak antennas on our computers. A couple weeks ago I bought an Alfa omni-directional high gain wifi antenna in hopes of improving all that. We are at a city park, with no wifi, parked on the edge of a lake. With this antenna, I'm picking up free wifi about 2,000ft away, but the signal was hit or miss. Today I put a hacker tinfoil parabolic antenna behind it, which doubled my signal strength.
Anyway, this gadgetry is absolutely priceless for any full time RV family, and it works great. I'm sure it will work well in traditional RV parks, where the wifi signal is often very weak.
$39 high gain, omni-directional antenna=3 bars. Add DIY hacker parabolic=3 bars. Totaling 6 bars and a solid internet connection across the lake.