This looks the original map I shared last year. I shut down at the end of this trail. I've seen plenty run it all the way to 1519, but I just don't trust it past this last waypoint. As mentioned above, there are some areas you can run on the south side of the lake, but there some bad areas also. I stopped running a lot of the south side after seeing what's really there back in the drought.
There is nothing but open water if you stay pretty much in the center all the way to 1519 - it's wide open. I live on the lake near 1519 and run it all the time. There is a new dock on the major south point about where the map from above ends. You can see stickups that mark the edges all the way to 1519, but you have a huge 50 yards plus lane running all the way to 1519. When the water was down, there was nothing out there but grass. I see these questions all the time about running Sandlin and wonder why. The lake is 20 times easier to run than Fork.
Here's a very rough map showing what I am describing.