I have found the time of day to have a lot to do with WIFI speeds at many campgrounds. Between 6 PM and midnight, mostly non-usable, but after midnight till mid morning or noon, they are much faster. Until a few years back, I still had a few clients that I worked with as a consultant. When traveling and I needed WIFI connections, first I tried the campground one, then I also had a Verizon prepaid MIFI device and account. Plus we have our cell phones with AT&T with a 30 gig, with roll over family plan. Currently we have 7 devices on that family plan.
As the billing month would progress, I might find I needed to add to my prepaid Verizon plan which was easy to do by credit card.
My wife likes to stream movies and I tell her to figure about 2 gigs of data to do so. During my consulting days, when traveling, I found we needed somewhere between 30 and 50 gigs of data a month available. When not traveling, I don't activate my Verizon MIFI device