It took me about 2 hours to drive from Raleigh to WS, but it was perfectly clear weather then. I'm not sure what it will take if its snowing/raining.
I originally spent $600 on a Travelocity ticket to get to Greensboro but missed my connecting flight in Chicago due to a snow storm that shutdown the airport. Last minute flight on Southwest (extra $200!) dropped me in Raleigh at 1am. That flight was also delayed landing in Chicago due to snow. I should have arrived in Raleigh at 10pm. I rented a car last minute also, cost me about $100 because I have no auto club membership.
All in all, I'd said fly into Greensboro for simplicity unless you're arriving early the day before and don't mind driving at least 2 hours.
gobruins