What should I look for in grasshoppers?

Yes, the map helps. It also helps when I can cross-reference to other sources with maps. In North Carolina, for instance, there are thirtysomething species; but after eliminating the ones endemic to the Appalachian Mountains (some of which are described as not having been observed since the type specimens were collected), and then eliminating the ones for which the habitat was wrong, that does narrow it down. I feel pretty confident about the complex at least; and as complexes are, in some non-splitter points of view, essentially species, I can be happy with that.