Re:Going to Charleson, SC in 3 weeks
I too love the Wreck. If you just turn in the driveway after Magwood Shrimp the building right in front of you is the Wreck.
I also recommend Seewee up Highway 17 in Mt Pleasant. There's still lots of construction between Charleston and it, but it's worth it. I also like Page's Okra Grill (mostly locals, prepare to wait on weekends). If you are on Isle of Palms try the Sea Biscuit for breakfast or lunch.
The Grocery is a new place on Upper King I like a lot.
If you want more upscale recs I can give you those too.