Around here, a lot of the trail systems are "homegrown" or at least grow organically over the years. The trails I ride the majority of the time are collectively known as the South Austin Trail Network. There is somewhere around 70 miles altogether, but there's no map nor is all of it necessarily sanctioned. The "crown jewel" of Austin mtb is the Barton Creek Greenbelt. There are good maps, but they will only show you the main trail, which you will hate because it's full of hikers and dogs and patchuli. All the fun back trails either require a guide, or years of exploring. And there's some seriously gnarly shit on those trails. I think the only places around here with good maps like you're looking for are state and lcra parks, and mtb specific places like Flat Creek or Spider Mountain. It sounds like maybe the dfw area is similar. I guess I just use the apps to sort of put together a route in my head based on the segments available. But it would be nice to have full maps of an entire trail system.