Really depends on the rider. If I do that ride I can get it done in about 2-2.5 hours. If you do the round-about climb for flow that climb is fairly mellow, it is the climb out of the bottom of flow up sulphur to braille that is ~40 minutes of hell. And then you have to climb out of the bottom of braille to get back to your car. One of my fav rides, but bring water and CO2, you are deep in the woods!
That's fast! I'd say for the average rider, the basic flow loop from the lot, up buzzards, down ridge, flow, up hihns etc is about 2.5hours, especially your first time there could be more like 3 hours. Add the braile loop, another hour, so about 3.5 hours total minumum.
Yep! Bring water, food, tools, and if you ride alone an inReach or other communication device. There is no cell signal up there except in one spot at the top. If you break something on the Flow or Braile trail or other point far from the lot, it is a very long walk out. It is much longer if you're injured, and alone.