I recently had the front wheel bearings repacked as mentioned in the Haynes manual for a service item. Does anything need to be done to the rear wheels? I commute 140 miles a day and want to make sure the vehicle stays maintained well.

NOPE...
Check the fluid level, details are in the manual....
I change the rear diff grease every 6 months, if your driving is all on the road, you can get by with every 60,000.
If there are no leaks in the rear, you should be fine.