Shoeman, the Renaissance downtown is still fairly new and nice. My favorite places to eat are: Shem Creek bar and grill for shrimp and grits -- over the cooper river bridge just north of Mt Pleasant; The Dock Restaurant for fried catfish -- located on Tailrace Canal just north of Monks Corner; Duke's for BBQ -- we like the one on James Island; or Kelly's BBQ on Hyway 78 near Summerville. We always like Kiawah for the beach over Isle of Palms or Folly. You can find plenty to see if you are interested in revolutionary and civil war stuff. I think it's worth the trip out to Ft Sumter to see where the invasion began. And the USS Yorktown is pretty neat especially if you've never been on a carrier. I haven't seen the Hunley display but I want to. Charleston is where my wife is from and where we met while I was at the AFB there. Pretty special place. As far as fireworks goes, I don't know for sure, but Patriots Points just across the cooper river bridge where the yorktown is located will likely have something going on.
I stayed at the SpringHill Suites Downtown/Riverview about a year ago. Had a balcony overlooking the city. Great view. Also the hotel offered a van that dropped off right in the middle of downtown. Very convenient and no need to worry about parking. As far as dining options, people flock to Hyman's for great seafood. I loved the hushpuppies. Not normally one of my favorite sides, these were worth the stop. I'd guess it would be hard to go wrong with fresh seafood almost anywhere in Charleston. Enjoy the trip.