Many years ago while doing research at the Ohio Historical Center on a railroad job, I killed time while I was waiting for various maps (they only let me have one at a time), looking into my family in the Civil War.  I found one somewhat amusing.  A twenty-three year old lieutenant who had a thirty-two year old uncle under his command.  I recall thinking that it must have been a somewhat uncomfortable situation for both of them.
I quite enjoyed Gettysburg, but I have to also recommend Antietam.  Such a massive waste.  Seeing Sunken Road just makes you shake your head regarding the strategy.  The site has been kept quite pristine.
For a good civil war read, I don't think you can do any better than Bruce Catton's trilogy.  I first read it thirty-five years ago in junior high, and reread it about ten years ago.  I agree with Lin that Ambrose is a great read also.