Never made it on the tour since the tour provider cancelled without notification. Showed up to the meeting point in time, no driver. Another driver told me to wait since they were likely picking up other guests from their hotels. Waited, and waited. He finally decided to give the main office a call. Lady at the office told him that they cancelled the tour. No attempt to make contact with me, no notification through Viator, no apology. Oddly enough, I received a follow-up questionnaire through Viator that reached me just fine. Thanks for nothing. Thanks for wasting my time, and leaving me hanging.
Advise to other travelers: skip this tour and use ride-share to get to Boone Hall. Lyft was ~ $20 one-way from downtown Charleston, no issues with pick-up at the plantation, and ticket at the plantation is $24 as of February 2020.