I don't think having a slight oversupply is a bad thing, especially if you are going back to work. .
Having a good supply is different than having an oversupply. An oversupply is always a bad thing. The term "oversupply" means your body is producing too much milk without enough fat it in it. Without the fat to help with the digestion, the milk shoots through the digestive system too quickly causing cramping, gas, and discomfort for your child. How on earth would that ever be considered a good thing?
Like pps said, I would wait until breastfeeding is more established and your supply is more regulated before re-introducing the pump. This will also help give you time to pump because the feedings will space out a bit so you won't have to worry about her needing to eat right after you pump. For returning to work purposes, I found that pumping once a day after my son's first morning feed helped to create a nice size freezer stash for me.