This Glen Gillett identified as being 47(1862/1863), born in Illinois to father born in Ohio, mother in Massachusettes, divorced. The immigration year and the "Pa" following (Pa means "papers." The enumerator was to use this term if the immigrant had filed their Declaration of Intention to become a citizen). BUT, this doesn't seem correct if he was born in Illinois. It "appears" the enumerator had err'd from those above and below, they being immigrants.
I find two family trees having "Glenroy O. Luzerne "Glen" Gillett, born 13 Aug 1862 in Illinois, died 20 Nov 1945 in Greenbush, Warren Co, IL. He had married Annetta Clem in 1891 but divorced. In 1920 he is living as being a widower, his son Chester is living with him.
As far as a construction camp, there does not seem to be enough information in the census to identify any company involved. Glen appears to be a lodger in the residence of Brown, who is a camp cook. Construction camps are so very limited in time factors, there are just no records kept on such activity. It would be hard to identify what construction these men were involved.