I'm amazed, absolutely amazed, that nobody has thought of the simple expident of a stick with a brightly-colored rope on it as a path marker. It works in neigh-any terrain, and a lack of air and gravity will do just about nothing to it. It even gives you an easy measurement system for your Cavorite-finding men.
Edit: seriously, the nerds need to just get their assess outside and start triangulation exercises. If your instruments measure estimated range, it takes three trips, tops. If your instruments take a bearing, also three trips. Then all you need is a pilot shaft and hey presto you've got Cavorite.