Interesting that you should add that. I am something of a Civil War buff. I'm maybe at CWB 103 in terms of book-reading and 102 in terms of site-visiting experiences.
Petersburg was nowhere on my list of places to visit. I imagined it (wrongly, evidentally) to currently be bleak and industrial. I'll think again.
If your into old plantations, highway 5 along the James river has 4 or 5 old plantations open to tourists, including the homes of 2 presidents. Berkeley plantation is the birthplace of W.H. Harrison and John Tyler's house is nearby.