I think part of the reason why they don't get volunteers there is today's political climate. You can't talk about a Southern plantation without acknowledging the fact that some people were held on that plantation against their will, as slaves to the plantation's owners--so people are afraid that if they say anything interesting or positive about a plantation at all, others will think they're condoning the practice of slavery.
Of course that's absurd--I've never met anyone personally, anywhere I've lived, who thought slavery was okay.
The practice of slavery in the US was wrong on every level--that's indisputable--but there is much more to American history, and Southern history, than the fact that slavery was once legal in the US. True history, politics, and culture are complex and nuanced topics, and we as Americans ought to be able to learn about and discuss them all freely. So I'm glad the plantation is open for tours, and I think it's great that you're volunteering there.
And when I mentioned people's different perceptions of different regions of the country, depending on where they grew up, I wasn't just talking about race relations, I was also talking about sterotypes about things like Southern accents and the use of the word "y'all." (Both of which I grew up with. And for your reference, the plural of "y'all" is "all y'all.")
The high sewer connection at your campsite, and lack of specific instruction about what your job was at first, are both indicative of an intangible aspect of Southern culture which was different than what I grew up with, and hard for me to get used to for a long time--a sort of "casualness," if that's a word. One aspect of Southern culture that I love, though, is that people down here seem much more open about their lives and feelings than anywhere I've lived before. It's common for me to have an hour-long conversation with a stranger at Walmart, for instance.