Thanks for all of the great advice!
I never thought my wife would be this into owning an island property (her first question when we started looking was "where's the driveway" I pointed to the boat launch

). But the way she has been calling all over to get this insurance has shown me that she is really on board and not just doing this for me (that is great news).
We have a few good leads and should have insurance by Tuesday. The information I gained from starting this post was invaluable, thanks to everyone who responded.
I will let everyone know the outcome and the names of the companies that were able to help. I can only wonder what this will do to island property values, but that is not why we are doing this, it is for our daughters and the memories they will gain from the lake.
Thanks again!