Out of those options I'd recommend PSL. It's larger and does things and its faults are plausibly reformable.
Also don't sleep on issue-focused left groups. They'll often be communists. The downside is that they usually have unique local names so you'll have to go find them.
What kind of work do you want to be doing? One way to find an org is to go to the events and actions you'd want to organize and finding out who organized them. For example, if you want to work on forming unions (presumably with a left angle), I'd recommend attending some pickets and start asking around to find some lefties.