Once the huts were well on their way to completion, Brumbaugh was instructed to begin another phase of the "complete restoration"—the rediscovery of Fort John Moore, popularly known as the "lost redoubt." Fort John Moore would have been an earthwork fort or redoubt surrounded by an open ditch or moat created by the digging of soil to form its walls. Tradition had it that Fort John Moore was one of two redoubts that would have been located at the northern extremity of the outer line, completing the chain of forts surrounding the encampment. Antiquarians referred to it and its sister earthwork as Fort John Moore and Fort Mordecai Moore, after the owners of the farms on which these structures had been built. Fort John Moore had been built shortly before Washington marched his men out of Valley Forge, and it had long since been plowed under by local farmers. Author Henry Woodman mentioned Fort John Moore in his 1850 history of Valley Forge, and the fort appeared to be indicated on some early maps of the encampment. The park commission found the documentary evidence "contradictory and confusing" and in the instructions to Brumbaugh emphasized the importance of accuracy and authenticity. 
Attempts were made to locate the fort using mine detectors to find metal relics that might be hidden beneath the soil. The Pennsylvania National Guard Military Engineers looked for the fort in February 1948, and the Second Army looked again in May. Neither came up with positive results.  Brumbaugh had heard that air photography was being used to locate Roman ruins in Britain and was eager to apply this new wrinkle in scientific archaeology at Valley Forge. Consequently, the Eleventh Air Force flew a mission for Valley Forge the week of May 11, 1948, and provided the architect with photographs of the suspected terrain. One picture showed a short and faint line in the grass indicating subsoil disturbances. Brumbaugh and Park Commissioner Norman Randolph, a former brigadier general, carefully located the spot in the fields at Valley Forge by relating it to trees visible in the pictures. 
The next step was conventional field archaeology. Military archaeologist J. Duncan Campbell was engaged to dig an exploratory trench. Right away he found "disturbed earth," which everyone interpreted as the ditch that would have been outside the fort. Dr. J. Alden Mason of the University of Pennsylvania became interested and cooperated with Campbell. The actual diggers were high school students on vacation, and when it became clear that they would have to report for classes before the excavation was done, Brumbaugh rounded up construction workers from another Valley Forge site and put them under the supervision of Mason and Campbell. Within a few more exciting days, the walls and moat of Fort John Moore were either uncovered or clearly indicated.  In all the digging, only one disappointing eighteenth-century relic was found: a small hand sickle. No other remains were unearthed except for some layers of charcoal and more suspected human bones. Fort John Moore was reconstructed entirely on the evidence of "feature archaeology," or the subsurface remains of a long-buried structure. 
No one knew what eighteenth-century soldiers would have called this particular earthwork, but Brumbaugh suggested that the fort's name be changed to Fort Muhlenberg because Muhlenberg's troops had been en camped closest to it. The Pennsylvania Historical and Museum Commission named it Fort Greene after Nathanael Greene, one of Washington's major generals. It is now known by the unsentimental name "Redoubt #2."
Having reconstructed the log huts and located the lost redoubt, the commission would take one more step toward re-creating the winter encampment with the construction of the Knox Artillery Shop. According to tradition, there had been such a shop somewhere near the old road running through the camp's artillery park (now Baptist Road Trace), a central location where the Continental Army's artillery was thought to have been collected so that cannon could be quickly dispatched in any direction in case of attack. The shop replica would be built near the artillery park's replica cannon and would be equipped with period tools. Demonstrations could be staged to show visitors how camp horses had been shod and gun carriages repaired.
Construction of the Knox Artillery Shop went fairly smoothly. The Second Army again used mine detectors to try to identify the shop's original location, but found nothing where this shop had supposedly once been. Although elsewhere they identified possible submerged metal within a 50-foot radius of a deposit of charcoal, their results were inconclusive, so Brumbaugh was instructed to erect the shop at its traditional site. Based on his knowledge of colonial blacksmith and wheelwright shops, Brumbaugh designed a building with wide doors and a wheelwright's bench appropriate for the operation of these crafts. The shop's equipment was donated by the director of the Fort Ticonderoga Museum in New York. 
The fourth jewel in the "complete restoration" crown was to be the drastic renovation of the Washington Inn, where hotel and restaurant operations had always been such a thorn in the side of the park commission. With its tall, round cupola and fancy balconies and ironwork, the Victorian Italianate Washington Inn also visually overpowered nearby Washington's Headquarters and dominated the park's major intersection. To tourists it had always been a landmark; to the park commission it was an eyesore. Park Commissioner Norman Randolph used that very word, calling it "an eyesore in grotesque contrast with one of the principal restorations designed to enhance the beauty and dignity of the Headquarters area."  Brumbaugh agreed. Like most disciples of the Colonial Revival Movement, he was devoted to the merits of seventeenth-, eighteenth-, and early nineteenth-century architecture. Brumbaugh referred to the renovation that had given the Washington Inn its Victorian Italianate features as "vandalism." 
In 1947, Brumbaugh began carefully peeling away the layers at the Washington Inn. When the cupola was dismantled, he encountered one interesting message from the past. On the back of an arched spandrel over one of the cupola's windows, a nineteenth-century worker had penciled the words "May 5, 1854—The son of a bitch that takes this down will remember Garrett Snyder, the son of Harry Snyder, Roxborough Town Ship, Philadelphia —G. Snyder foreman for Sam Rau, Wages $2 per Day."  Undaunted, Brumbaugh proceeded with his careful demolition and eventually identified six or seven stages in the structure's history. He concluded that an original log cabin had been rebuilt as a stone dwelling, which was subsequently expanded into a long, two-story house around 1758. Later a rear wing had been added, which Brumbaugh interpreted as an adaptation that converted the house for the simultaneous use of two different families, A major reconstruction had occurred sometime after the encampment around 1790. This had been followed by the "vandalism" of Garrett Snyder in 1854, which had been further adapted about twenty years later to transform the house into a hotel.