following on from what Codd said about planning, the editing work might not be too difficult but it is, of course time consuming. depending on what you are going for, someone with a heightbrush could complete the hills rather quickly, as the heightbrush on a low severity makes low hills really quickly and smooths at the same time and doesn't create the awkward 45d shapes that the erode brushes often create.
When planning, remember what kind of area your in and how the redfork (it is the redfork, right?) might affect the east of your project.