Hi Dagny. Wow! 200 is impressive.
That kind of information is very helpful. Who knows? Maybe there's something Sol can do to automate a transfer of works like yours. Do you have an offline backup? Please say yes. 
By the way, Sol's been on vacation, which is probably why he hasn't commented.
Your don't have to worry about banking information. There are too few of us left to make an automated account transfer worth doing. It would take much longer to code and test than it would for the rest of us to simply go to Booksie, open an account, and repost our work. Yours appears to be one of the exceptions because 200 is a lot.
Have you ever been able to back up your poems en masse onto a thumb drive? Just curious.
As noted in my original post, Sol hasn't made a decision as to an end date for TNBW, but he doesn't have the time to keep running both indefinitely. Unfortunately, we're not converting enough (any?) new users to replace the folks who've left, and as a result, the site is at a virtual standstill, at least as far as book chapters is concerned.
Are new poems still being posted in any significant numbers by others besides yourself?
I'll be taking over some of the admin and maintenance tasks from him in the coming weeks, but I have neither the full skills nor time to take care of the whole system. And as you may have noticed, we're not getting bug fixes or minor enhancements, to say nothing of the implementation of new features like those he's built/building for Booksie.
Right now, this is fact gathering mode. Given how similar the two systems are, the obvious place for us to go is Booksie, but there are issues that need to be addressed as discussed in this thread. Hopefully, it's just a matter of getting questions answered re how best to do things on Booksie (eg how to prevent exposure of our work to the internet since that would be a show stopper).
There is a TNBW group on Booksie that we should all join so we can find each other over there (user ids may be different). Sol's most recent post on this site (the reminder about the free year on Booksie) includes a link at the top of the thread to that group on Booksie. Be sure to add yourself as a member, otherwise you'll never find it again (it's private).
The most obvious workflow for us on Booksie is an Advanced Writers group of our own as discussed in this thread. I'm trying to work out the details of how and whether that will work, and a list of issues/questions I can take to Sol.
Please keep your feedback coming.