Not only has my missing cat turned up safe and dry, but I just got a call from our contact person saying that she'd just been notified by the town that the state has approved the request for a temp bridge. It will take two days to install, and they will start on Sunday and finish on Monday, and with luck, we should be able to get out on Tuesday.
It will remain in place until they engineer a better solution for the brook.
I have decided it is no longer necessary to ration my Klondike bars and am celebrating by eating one. (Would Klondikes have counted as emergency supplies? Would they had made it over the ridge on an ATV? Hopefully, I won't ever find out!)