Because we have been to both a number of times and even in the same spot with our prior pop-up and now 23 foot hybrid I had to look, your correct Johnson Branch maximum length sites according to the reservations page are 5 feet shorter.
As noted above our hybrid fits in the same spot the little pop-up did but it is no where near the length of the site.
In the past it used to be much easier to get into Johnson Branch than Isle DB but now more folks have found it. sigh...
JB is not quite as busy in the summer for day use (done that) and has more natural shade over the picnic spots so go figure.
