I plan on being there on 2013...I’ve been with my boys a few times, the last time for the rally in the park on July 4th...agreed, you should go. General rule of thumb on going; give yourself days, not hours, take the walking tour, stay the hell out of the bus (unless you aren’t mobile) and the tour guides are good, but some forehand reading and mapping won’t hurt.
The tale of the lost ground at round Top is that Lee made the mistake of saying “take the hilltop when practicable” and they thought he said practical and figured it wasn’t. Too bad...southern gentility screwed them pretty badly.