Are we talking 50k people per town? So over a quarter of a million people in total, each with more connections to other people outside said towns?

I applaud and encourage your chutzpah, but I’m not too optimistic about your prospects. Do you want to move your community out of Facebook, or does the community want to do it? Do they even agree with your reasons for wanting to move, or is it possible they actually agree with Zuckerberg and voted for Trump?

Remember you only have one shot. With that large of a group, you’ll find people with all levels of skill, patience, and ideology. If your solution isn’t immediately better (not equal; better) than Facebook, you already lost. It doesn’t need to be better at everything, but it does need to be better at the most important and most used features. And make sure you believe in the cause enough to be the goto person for every question.

Make a list of what the platform needs to support and do and come back with that. Then test, test, test. You won’t succeed if you rush, people move slowly.

Best of luck to you.