It depends. There are several wrecked cars along the way. If you go beyond the falls, you reach a closed campground and eventually the road that the cars fell off of.
My watch mapped it at just over 3 miles round trip and it took us 2 hours. We're slow and we climbed down to the base of the falls. Nice hike.
Roughly about 2.9 miles, but it will feel like 4 miles though. That's just my opinion.
Thanks! Your answer is awaiting moderation.