How important is TV too you? For many people, it is so important that they buy satellite TV service. Others never turn their TV on when RVing, TV is one of the things they are getting away from. I have friends who do not even have TV at home, it is just not important enough in their lives, but they do have computers and are on the Internet.
Any TV you buy new today will receive over-the-air digital broadcasts. The antenna that comes with your TT works for this. You raise the antenna, point it directly at the TV station's antenna tower or repeater. Most TVs have signal strength tools to help with aiming.
How far broadcast TV carries depends on the broadcaster's power, antenna height, and terrain. UHF, and the little VHF still used, is line of sight. In central Florida, we could regularly pick up stations 50-75 miles away. Expect the same in other flat areas with few stations broadcasting at high power. But in the Rockies, we sometimes could not get a station 20 miles away if it was on the other side of a mountain and we were down in a valley.
In NE Oklahoma, edge of the Ozarks, I have similar terrain to western and central Tennessee, mostly plateau 600-1000 ft above MSL with at most a few hundred feet of sharp relief in valleys. Atop a hill, I can pick up stations 30-50 miles away, but I may have to choose between aiming the antenna at one city or another, or yet a different direction to pick up a nearby low-power repeater for the PBS station.
If I am down in a valley, I might not be able to pick up a station 15-20 miles away. At our COE parks, if we want a waterfront site, it might not work so well for watching TV. Or for cell phone reception, as well.
Digital broadcast TV has changed effective distances, because it is sort of all or nothing. Where an analog tuner could bring in a fuzzy image from a weak signal, digital might be intermittent or just not there. I live in a place where the transition to digital moved me from "fringe market area" to "out of market area" but if I take the RV to a nearby hill I can pick up stations that don't get to houses in town, which is in a river valley.
Cable at RV parks has been changing. Around 2000, when cable providers started adding digital channels to their analog lineup, RV parks would repeat the untrapped analog stations by coax out to each parking site. Franchise rules at the time were that "local" broadcast stations had to be carried analog, and other content providers (direct marketing, religious stations) usually contracted with the cable company to be carried the same way.
"Premium" services were carried digital, some in the clear so a "digital cable ready" TV could show them, others encrypted or trapped so that you needed a cable TV receiver, or sometimes a "cable card" for a "cable card ready" TV.
Since, more and more cable providers have been going all-digital (mine is one of the late ones, working on the transition right now). If that happens at a RV park, you'll need a digital cable receiver (or card) encoded to be recognized by the park's cable provider. This might be loaned to you "for free" (meaning cost is included in your fee, whether you want the service or not, on the hotel model) or it might be rented to you on a daily basis, to cover the per-customer fees charged to the park operator by the cable company.