When looking for antonyms for the term "most long-range," we must first interpret what the phrase means. Indeed, "long-range" implies something that can go a long distance, last for a long time, or be planned over a long period. Therefore, possible antonyms include words such as short-range, short-term, narrow, limited, and brief. For instance, if you're considering a "most long-range plan," it would be utterly opposite to a "short-term strategy." Similarly, one wouldn't describe a "limited budget" as the "most long-range financial plan." Therefore, depending on the context, there are plenty of antonyms that can contrast the meaning of "most long-range.