I've settled today with my family at a cozy and comfortable rental where we have power and water, and wanted to respond first to thank all of you for your responses -- I'm so grateful for the kind words and information.
I have confirmed what @Garrett Brown shared -- my best option is an SBA disaster loan with a lower than normal interest rate to pay off our mortgage and then I can also hope for / pursue with others a land buyback program for those of us who have floodplain property that FEMA won't reinsure. So much of the land was just taken by the river anyway -- it just re-routed itself and swallowed up most of the land on the riverside of the road.
I do have one more favor to ask -- if anyone has leads on an accountant that can jump in to help us file last year's taxes by late November, I would be grateful to hear -- I still need to get them done, and especially need them done in order to apply for the SBA loan by the December 2 deadline. Had a plan for a January completion, but need a new plan!
Thanks again,
@Garrett Brown