GW, drive from MB to Columbia is only about 2.5 hours, depending on which part of Columbia/MB you're headed to/headed from. I'm on the Florence side of Columbia and can be there in that amount of time during the off-season since you won't really have any beach traffic to deal with.
And, you're right, there won't be many cars on the roads down there at all. My wife and I were down last Christmas on Dec. 23 and MOST of the restaurants in the area were even closed for a couple of weeks, with several set to re-open in February.
Shoot me a PM and let me know when you'll be in Columbia/which part of town. Love to ride with you and get to know a few others here on BF.