We dropped people off at Brandywine Bay once. There is a small concrete dock on the east side that you can dingy up to (well, it was there 10 years ago). Cab driver picked them up at the dock. You probably don't want to walk to EIS from there. You have to thread your way through the unmarked channel with rocks on either side but it was easy since the channel goes right in the center and the water is so clear. I don't know about the depth but we took 44' cat in there.