“2,000 cubits.” Scholars estimate that a standard cubit was about 18 inches, so 2,000 cubits would be about 3,000 feet (about 1,000 yards; 914 meters; .57 miles, or just over half a mile).
“before.” The Hebrew text uses an interesting idiom, and literally reads, “yesterday and three days ago.” It means, “before, formerly, in the past,” and gets translated “before” in many English versions. So in the idiom, the current day would be day one, “yesterday” would be day two, and “three days ago” would be day three, and the idiom would then use that to refer to “before.”