About how far from the ark were the people told to stay as they followed it?

Answer: 2,000 cubits

The people were to keep a distance of about two thousand cubits from the ark, yet follow it, since they had never traveled that way.

“But keep a distance of about two thousand cubits between yourselves and the ark. Do not go near it, so that you can see the way to go, since you have never traveled this way before.””— Joshua 3:4 (BSB)