Newbie in Charleston, How to Spend an Afternoon

I think all of Brew's ideas are spot on. I will add, though, if you do go on any of the tours (walking or carriage) bring some cash cause they guys really appreciate tips. Plus the guide will probably be more than happy to name a couple local spots that are running specials for dinner or drink spots. Speaking of which, one of my favorite bars was Wet Willie's, simply for the novelty of it. They have a ton of Icee style drinks that taste amazing and will get you feeling a little loose for pretty cheap.  

Rough part of only having the afternoons, is that most of the plantations and really interesting history things would be closed by the time you get there. But if you do get a Saturday or half day or anything, definitely check out Boone Hall Plantation, Drayton Hall or Magnolia Plantation and Gardens. Google "Charleston plantations" before you come down and you can choose which one is easiest for you to visit.

I think Charleston is one of the best cities in the World and even if you only have a few hours, its a great place to spend some time.  

I would definitely recommend doing a carriage ride, I think they all are pretty much the same, but I think Palmetto Carriage Tours is a good bet.  They run about an hour and give you a great overview of the city.  If you want a more in-depth tour of the city, definitely do a walking tour.  Charleston Sole will give you a great understanding of the city and well worth it.  Can't recommend a walking tour enough.  If you have an afternoon, that would be plenty, then I'd just bar/restaurant hop, as the city has some incredible food options.  I'm a college fan, and I think the  College of Charleston has a very nice little campus, and may be worth a stroll through (but I would do the carriage/walking tour before heading to the campus).

Outside of that, just enjoy some of the incredible food and bar/restaurant hop.  Amazing food and restaurant choices that really highlight the city's culture.

Hominy Grill is the quintessential breakfast/lunch place for southern comfort food, Husk is one of the best restaurants in the country, Slightly North of Broad and  Magnolia's,  are standards that serve great food in the heart of town.

Lots of good nightlife options with plenty of live music, etc., to be found.  I personally love the Roof Top Bar & Restaurant on the roof of the  Vendue Inn for as a great spot for a drink with a view. 

One of my Favorite places to visit! Of course you must ride through downtown Charleston Historic District to see the magnificent old homes. I do hope you are staying in a hotel downtown. It is worth the extra expense since you can walk most anywhere you want to visit in old Charleston...history, restaurants and shopping. We love to stay on Meeting Street which is the heart of the city.  If the weather permits, a carriage ride through the old town will give you splendid views of the homes and a great history lesson from your guide. Well worth your time. You will find the tour stations in the Queen Street area near the Old Slave Market Museum which is another must. Map link -   http://www.planetware.com/tourist-attractions-/charleston-us-sc-char.htm   Be sure to travel down Meeting Street to South Battery Street to visit The Battery to take in the splendid view of the Ashley River and Cooper River and gorgeous riverfront homes and walk under the sprawling old live oak trees.  2 links below -  https://www.google.com/search?q=battery+park+charleston&client=firefox-a&hs=keH&rls=org.mozilla:en-US:official&channel=sb&tbm=isch&tbo=u&source=univ&sa=X&ei=g9gIU4OKMeXEyQGNgYGwDA&ved=0CC0QsAQ&biw=1366&bih=701     http://www.dreamcharleston.com/charleston-battery.html  If you like antiques and art, King Street is a must. For a good Southern Low Country meal experience, we enjoy Poogan's Porch. It continues to have good reviews after 30 + years of business. Welcome to the South! I hope you enjoy your visit.

I hope you get some warm weather while you're there!  While Kings Street is a tourist attraction, I always seem to have the most fun on and around Market Street. I've been to Charleston on day trips too many times to count. So close to Charlotte!!  Definitely take a carriage tour.  Even if you're alone, they will put you in a carriage with other people traveling alone or in couples. The  Red Barn Carriage Tours is a good place to start. The tours provide information on history, architecture, botany, and culinary arts!  A great way to get your feet wet on a first trip!

You can walk around The Battery and explore Old City Market. These are both things that you can do when you get free time.