Do you know of any documentation to get SSB bootstrapped? I tried several times, but I hit a wall of not being able to find any active communities, plus there were old-style, technically obsolete communities and new-style communities, and half the available documentation referred to each, so it was impossible to figure out what to do.

Nope, same issue myself.

I find it fascinating to read about, but it seems to have a steep and very slippery social hill to climb before the technical parts of the network do anything.

I'm fairly certain there is not a working implementation of ssb in it's original form anymore.

But yes, it had local wifi sync.