I have spent some time on 4th Machias and remember watching moose every morning in the bog at the western end of the lake. Dale Toby, a canoe builder and guide from Grand Lake Stream has alot of history on that lake, his grandfather had the first camp which is right at the put in now, he used to walk in before there where roads, probably from West Grand Lake. Dale is a good guy and could probably help you out with info. I sent his email address in a pm.
Robin