I would raise the car in the back and spin the wheels to make sure it's the wheel bearing and not the differencial or a u-joint.
Look in Chiltons manual to see what you are getting into. It requires special tools to loosen the nut on the back side of the hub. They show a flange that bolts on in place of the wheel with a tee to put a bar through so you can use it to keep the hub from turning while you loosen the nut. It takes a lot of torque to break it loose. I've never done it but I wouldn't be afraid to try. If you have an impact gun , you might be able to just put the tire back on, lower the car and drive it off with the gun. I just read this and it seems cofusing to me to! If you want, I can email the pages out of the book. Contact me at thomasramsey@msn.com
Good luck

 

I would suspect a U-Joint before the rear wheel bearings. U-Joints tend to need to be lubricated or replaced 2 - 3 times in 100,000 miles, where I have only once needed to go in and replace a rear wheel bearing, and I believe that was on an old 69 510 Sedan I once owned.

You have four U-Joints in the rear, I would suspect one on the rear passenger side, where most of the water gets tossed up, and the torque/spin occurs first when accelerating.

Speed

Enjoy the Ride!