For starters, he would have had access to historians who today interpret the battle with hindsight. He also could have had a battlefield guide, compliments of the National Park Service, and he could have checked the weather - especially on that third day when it was so blasted hot. He might have decided to delay the gallant - albeit hopeless - charge of General Pickett's approximately 15,000 men.
But alas, with only binoculars to see down the road, mistakes were made.
In mud, in the pouring rain, Lee on the fourth day began his retreat to Virginia.
President Abraham Lincoln four months later made his famous Gettysburg Address. And that "great battlefield" consecrated by the "brave men, living and dead" eventually would be preserved with an army of monuments.
An area man and his brother, using modern technology, have done their part to preserve the history of one of the most studied and storied battles in history.
Dennis Lawrence of Kansas City, Kan., and his brother, Bob Lawrence of Houston found a ready audience of fellow enthusiasts on the Internet, some from as far away as South Africa, Australia, and the United Kingdom.
"Bob and I are Gettysburg nuts," said Dennis, who teaches English at Washington High School in Kansas City, Kan. His brother is a certified accountant.
The two brothers trace their Civil War passion back to childhood when they pored over maps and pictures in The American Heritage Picture History of the Civil War with narrative by Bruce Catton.
They made annual pilgrimages to Gettysburg and shared early morning coffee on Little Round Top, where Union Colonel Joshua Chamberlain made his famous bayonet charge against the oncoming Confederates the second day of the battle.
So far the discussion group has 600 members. The group will celebrate its two-year anniversary next month.
Biographies of group members show the unlikely mix attracted by the subject Gettysburg: a marine orintholigist from Cape Town, South Africa; a federal government employee who refers to herself as the Manassas Belle after the Virginia city in which she lives; and an official with the National Library of Australia.
"I don't think any other moment in American history draws such a diverse group of people," Dennis Lawrence said.
The group is planning a muster on June 6-8. As many as 200 members are expected to attend so they can meet people they have been talking with on the Internet.
While the Lawrence brothers are glad to see the public interest, their overriding goal is to make the discussion page a premier research site for the Battle of Gettysburg.
"We have a lot of people in our group who are authors," Dennis Lawrence said. Among the research material on the Web site is an index of general reports on the battlefield from 1893 to 1920, and the artwork of Don Troiani, considered by many to be the premier modern-day artist of Civil War subject matter.
Discussion categories are divided into the battle's three days and its aftermath, and they include such topics as strategic positions, hero worship of Chamberlain and Picket's Charge.
The aftermath category includes topics related to Lee's retreat, the Gettysburg Address and battlefield monuments.
The web site offers a daily weather report of the town.
Who needs that?
"People who plan to visit," said Dennis Lawrence, "Or people like myself , who sit around at night and wonder what the weather is like in Gettysburg."
The web site address: www.gdg.org
To join, click here: