An absolutely incredible way to see and experience Charleston, I wholeheartedly recommend you fit this two-hour tour into your visit.
We scheduled an 8am tour the day before (playing it fast and loose with availability, but we got lucky, I do recommend you book further out if possible). The earlier tours of course will be more comfortable because they're much cooler. You will be walking quite a bit on the walking tour, but the pace is very manageable and there are opportunities to sit a bit at various stops (my mother had knee surgery a month prior and was very able to keep up throughout). We also had a stroller with two kids in it on the tour, and with the determination of the parents & kindness of strangers the group was able to navigate the stone streets and lone set of stairs.
Bill (the tour guide and proprietor) was very familiar with the city and eager to share what he knew. He approaches the tour from an economist-perspective, rooting all of his stories in trade, industry, and profit (a great way to help you remember it all and see how the city has changed). He's also quite candid about the entire history, including the prominent role of slavery in the success of Charleston (other guides may gloss over this in fear of awkwardness). The children on the tour seemed to enjoy walking around but the content of the tour is geared more towards a 15+ crowd IMO.
Bill was a great guide, with answers to all of our questions and enough of his own to keep it interactive and engaging. Though his delivery slights toward pretentious at times, I came to realize it's really enthusiasm and commitment (he had to have been a professor in a prior life).
Again, wether it's your first or fourteenth time in Charleston, I'm confident you'll learn something new and be so glad you did--please join Oyster Point Walking Tours for a portion of your trip!