I would suggest she weigh how often (and at what time - 8 am YIKES!) she'll be going to work versus visiting you. I live in SW Durham and drive to Raleigh now and then for various reasons but would not want to do it during rush hour and certainly not twice a day
SW Durham is about 40 mins from Garner.
If she is really set on being somewhat closer to your family what about Morrisville or Apex? If in Apex, 751 could be an option. There is a verrrry long stretch with no lights and is a pretty drive.