I was trying to look at Nimueh's jpg in #18 on this thread, specifically at Gladitor's point on the border of TX and OK.
That border is the Red River (red like blood?), and looks like it's somewhere between Gainesville, TX and Paris, TX, give or take. There's Caddo National Grassland there, named after a Native American tribe, but I've run out of time for the day to look further into it and see if any of the clues fit anything in that area.
If anyone else would like to poke about on this train of thought while I can't, feel free!
Also, the other end of the same line looks like it lands flat on Havana. I found an area a little further inland called Artemisa. I didn't get to look into the potential for shipwrecks just off the coast yet.