How much time can I expect to spend here?

Don't take a tour go there directly to the plantation there's people there that will give you tours and there's so much information so much history you can spend a good two three hours depending on how much time you want to spend there cuz there's so much to see.

Depends on if taking pics and doing tour we usually are there 2 to 4...if we eat at restaurant...

1 or 2 hours is enough