I also replaced all rear bushings. I dropped the rear axle for that. Thats also a great time to refurbish the rear axle, diff, etc
All painted, glass beaded etc etc:
As far as the easy ones, they're the rtab's and the outer control arm bushings (and the rear arb bushings are also easy if you have the car in the air).
As far as importance, the rear diff bushing is a known wear point, but the diff has to come out to replace that one.