Overall
When Benton MacKaye wrote his regional planning article in 1921, he envisioned nonprofit community camps that would help in the trail development. He wanted to include food and farming camps as well to provide jobs, thus improving rural economy. Part of this plan was not turning it into a for-profit real estate endeavor, but as a nature conservation for recreation and work at one spot. Federalization made sure to keep MacKaye's project of conservation, sustainability, and community going... but turned the project into real estate through use of tools such as easements and eminent domain, which created some dissenting arguments of encroachment and government aggression for the private landowners on the trail; this was regardless of what tool was used.
Community oversight was used heavily to appeal to landowners who opposed the land acquisition.
Eminent domain was extremely risky, so the government kept the community aspect going by using volunteers to get landowners to accept the land acquisition by giving them other options of handing their property over to the government for public use. That community oversight was what made some people feel more secure, thus being able to advance the Appalachian Trail into what it is today. Easements were a better way to create the trail because it kept community oversight intact even with new and improved federal oversight of 1978; landowners can give their land rights for money, while retaining ownership of that land while it is publicly used.