The plateau is the flat-topped country separating Middle Tennessee from the eastern valleys. It runs northeast to southwest, it is cut by gorges considerably deeper than anyone expects on first look, and its edges hold a concentration of waterfalls with no equal in the state.
Get the geography straight before you plan anything, because the single most common mistake is treating it as one place. It is three trips. The northern plateau around Jamestown and the Big South Fork country. The South Cumberland around Monteagle, Tracy City and Sewanee. The western escarpment, where the land drops away toward the Highland Rim and where most of the waterfall traffic goes.
Access is the thing to understand next, and it is where guidebooks tend to be a year or two out of date. A great deal of the plateau is private. Some of what looks like state land on a map has parking for eleven cars. Several of the best-known trailheads fill before nine on a good Saturday, and the overflow parking that used to be tolerated on the shoulder is now ticketed in more than one spot.
Two practical notes that will save you a wasted morning. First, the plateau makes its own weather, and a forecast for Chattanooga or Cookeville tells you very little about what is happening on top. Second, phone coverage is patchy to absent across large sections, so whatever navigation you intend to use, download it before you leave the interstate.
Seasons matter more here than in the mountains proper. The waterfalls are worth the drive from roughly November through May and are frequently a trickle in August. That is exactly when the visitor guides run photographs of them at full flow.
The finished guide will carry an At a Glance box with seasons, road conditions, trailhead capacity and the parks that now require an advance permit, so the parts most likely to change can be updated without touching the rest.