Commercial campgrounds have no to weak Wifi, public parks generally none. There are of course rare exceptions................
I agree with the posters saying you must have your own Wifi hotspot to count on being able to get online. There are of course areas where signal can be weak or not existent. Streaming TV would get VERY expensive VERY quickly.
We have a satellite dish and Direct TV (or Dish works too) and the monthly cost of that is less than paying a major price for lots of data. Normal email and mild internet surfing does not use a lot of data. This works in areas even where there is no internet signal as long as you have no deep tree coverage. Just a thought for you for TV.
Good luck with your new adventures!