Very sorry to hear about your trip, it sounds like it was the weekend from hell.
But onto better thoughts....
If you are looking for a true native low-country meal at a family friendly price try a small restaurant called Jestine's. Great southern fare.... I love the fried chicken! Check here for address & phone #:
http://charleston.diningguide.com/data/d100187.htm
It is hard to compare any St. Patrick's Day parades against Savannah & NY City but Charelston is fairly rich in its Itish heritage so try these events:
http://www.704kofc.org/stpat.htm (broken link)
However, if you have the time to travel to Savannah, nothing tops that parade and the festivities that follows although the tradition of the NYC parade is something to experience, too.