Plan on spending 2 days there as I want to see as much as possible of the entire battlefields.
As I told you in the other thread, be prepared for huge crowds in June, that's prime visiting season.
Make sure you go to the visitors center and check out the panorama and the artifacts there; it's not anywhere near as good as the old one, sometimes new is not better.
Make sure also you hire a guide, tell him what Rebel unit your relative was in, he'll take you out to the spot on the field where they fought, they are a wealth of knowledge. One day on the battlefield is more than enough, probably the limit as to what your family can tolerate as well. You can spend the second day visiting museums and the town itself.
You can park you vehicle anywhere you want pretty much along the battlefield and walk all you want as well; I've done the Pickett's Charge walk, Ewell's assault on Cemetery Hill, the fighting around the Herbst woods and McPherson barn, the fighting around Oak Hill, Barksdales Charge, Hoods assault on Devils Den and Little Round Top.
The three most crowded spots on the battlefield are Little Round Top, the Copse of Trees at the angle and the Virginia monument, that's where Pickett's charge kicked off, a lot of southerners flock to that spot, they stand there with this glazed over look on their faces, the old woulda, coulda, shoulda feeling sweeps over them and they wander around like extras from The Walking Dead, so be prepared, maybe take your LET'S GO O'S!! ballcap off and have your own personal moment on that spot.
Pickett's Charge was nothing short of suicide, you'll understand that if you walk it, at certain points, you're totally exposed in the field, at one point in the charge, they were flanked on both sides, taking fire from three sides if you will, just a foolish decision by Lee.
Each time I go, I spent time in one specific spot; this year will be where the 1st MN charged on the second day; 262 men held off over 2,000 Rebels, the 1st MN was almost entirely wiped out in their attack, but they saved the 2nd Corps *****.
The Union Army fought with a purpose at this battle, which is understandable as it was on Northern soil, a much different proposition than the fighting up until that point.
Everytime I go there, I'm filled with great pride that the Union won the battle and it was the high tide of the Confederacy, then I am saddened that so many gave their lives fighting for what they believed in, then further saddened to think Americans were killing Americans there, it's all so sad.
You will get a great sense that something terrible happened there, the place has this feeling of dread hanging over it, can't explain it, but you'll feel it too.
DO NOT get one of those cheesy auto tour tapes to listen to, a 6th grader could tell you more about the battle than those things do.
None of the gift shops sell Rebel flags anymore, so if you want to put one in the area where your relative was, you'll need to bring your own, I see little flags all over the battlefield, people leave them in various spots.
Oh and take care of business before you go out on the battlefield, there are no latrines on the field.
And DO NOT eat at General Pickett's Buffet, the food tastes like it was leftover from the war and brings me back to my point about no latrines...................