Greg Gerritt, a leader of the New England Green Party, wrote a history of the Green Party for the years 2002-2004, called Green Party Tempest: Weathering the Storm of 2004. It is 70 pages and can now be read electronically at this link. Thanks to Jackie Deveneau for the link.
I hope this is eventually published along with Howie Hawkins’ book Independent Politics in one volume.