The whole galaxy will be destroyed by then. Once you get into the EU, dozens of planets are destroyed. Mon Calamari ravaged by World Devastators, an entire solar system evaporated by the Sun Crusher, planets virus bombed to hell and back. I expect by 4000 years after the events of ROTJ, there won't be many habitable planets left, and most races will be extinct. You'll have self-sufficient colonies trying to eke out an existence in space, and outlaws and nomads plying the space lanes. Any Jedi that exist will be akin to monks camping out during the Dark Ages.