There are some long threads on this. As I understand it the big problem with WIFI boosters is that many RV parks have low bandwidth WIFI. So amplifying that signal gives you a stronger signal but does not improve the bandwidth. Which means you can connect just fine but still cannot download anything.
So yeah you may be able to boost the signal but will the park give you enough data (bandwidth) to work with?
I've been looking at Cell Phone Boosters but they have obvious drawbacks, mainly you have to buy a bigger data package from your cell company. We had problems with AT&T landline and finally cut the cord, they kept adding stuff on the account that we did not want or need. My wife would call them up and complain then 2 months later they'd do it again.