The architects would know a whole lot better re construction but Merion is on 120 something acres, right? So, as Tom states. You can build the course on that acreage. However, if you're truly talking about a "Championship" course, with ideal room for bleachers, hospitality tents, gallery flow, restrooms and all the other stuff you need to host a "Championship" the way modern spectators and governing bodies routinely expect/demand, you need at least 200 acres. Probably 220.