Rosollia, thanks for the link to the editor. I downloaded it for future use.
Andy, yeah not having a dedicated backup was a big mistake. I won't do THAT again.
John, yes I saved it, reopened that save & reset the map size. Thanks for the tip on the bridges.
Thanks for the help and suggestions.
I just ended up starting over from scratch. I built a generic open water base map to use in the future and saved that first. I was hoping to convert all of the map edges to open water, but the build beach option only clears the left and right edges. That should be good enough.