"It's taken a few years to get to the point we're at now. We're hoping to have a good turnout of spectators," said Pratt, a general in the Confederate's Valley Division of re-enactors.
The re-enactors will camp in a field between U.S. 340 and Charles Town Races.
The encampment will be open to the public beginning at 8 a.m. Saturday.
The battle starts at noon on Saturday on Washington Street in the downtown area of Charles Town.
The re-enactment probably will conclude at the courthouse.
Pratt said he is not basing the re-enactment on any single battle for Charles Town, but is taking "bits and pieces" from reports of several of the engagements.
There will be a parade through town at 2 p.m. on Saturday. At 8 p.m., there will be a military ball in the Civil War camp, followed by an 11 p.m. ceremonial night firing of cannon, Pratt said.
At noon Sunday, four Confederate cavalrymen will race their horses against four Union cavalrymen at the Charles Town race track, Pratt said.
The Blue-Gray Classic Horse Race will take place on the straightaway of the track, about a quarter-mile race, he said.
The organizers decided not to run the entire oval to protect the horses, he said.
"These are not thoroughbreds with jockeys on their back. These are farm horses and riding horses with fully equipped soldiers on their back," Pratt said.
An estimated 400 re-enactors and more than 100 civilians in period dress are expected to attend, he said.
The re-enactors are coming from 14 states, while one cavalryman is flying in from Great Britain to take part, Pratt said.
Last year in the first-ever event, an estimated 2,000 spectators attended on each of the two days, Pratt said.
Pratt has been a re-enactor since 1985. He wanted to join an engineering unit, but could not find one. The engineers made topographical maps, dug rifle pits and built bridges for the soldiers.
"I was a Seabee in the Navy from 1960 to 1964. The Confederates were a lot like the Seabees. We didn't have much," Pratt said.