Paul, I believe those distances you quoted are accurate although I did not measure. However, you cannot go wrong. Just remember left, left, left on way in and right, right, right on way out, ignoring all the other intersecting roads. Anything just barely an inch higher than my car will be just fine without any off-road experience. I did not scrape my bottom at all although in some spots had to be very, very careful in navigating the holes and dips.
If you stop by video at about 4:30, I purposely zoomed onto my GPS about a mile from the Bowen Ranch intersection coming back and as you can see, the thing doesn't even know the road exists.
I was thinking from a security perspective, one possible solution is picking up a small surveillance cam. I recall Rick posted a link to one in an older thread. Or bring a car cover for a newer vehicle. Or pay jobe to watch it for you while you soak :-)