Each of these homes are owned by the City of Roswell and they are operated as House Museums. You can buy a pass to all three(which is good for a year, if you are local) at each of the homes or at the visitors center, which is also interesting.
The Smith Plantation has the most out buildings… and at different times of the year or for certain events they have them all open to explore. It was sort of modernized in the 1940s/50s by the last members of the family to live in the home.
Roswell Visitors Bureau:
617 Atlanta Street, Roswell, GA 30075
Historic House Museum Tours
(link to the Roswell house tours information, good as of 12/2020)