I am not a decendent of this family either, but I did personally know some of them as a young child, so I know what I am looking for in the census.
First off most of them lived around Green River, Wyoming, Sweetwater county. Green River was a railroad town and Jack Zimmerman and Howard Petre both worked for the railroad. Nels Philbrick married Mable V. Williams and she was from a ranching family. The family ranch was covered with water when the Flaming Gorge dam was built. He moved the old ranch house (that belonged to the Williams family) to Manila and they lived in it until they died. Mable was the county health nurse there for many years, the only doctor the town had at one time was Fay W. Tinker who died in 1933 and she attend to people that were ill. Nells operated a gas station and repair shop for many years. In the obituarty of Pearl Zimmermans she mentioned the family cabin, which was on the mountain south of Manila Utah.
According the the 1920 Census of Sweetwater County
John Jr. Widic was age 26, he was morn in Austria and immigrated to the US in 1905
Pearl E. (Philbrick) was age 18 born in WY
Elmer John Widic the son was age 4 months and 12 days
Charles Philbrick age 52 born in WY
Charles Jr. age 14 born in WY
Ada age 16 born in WY
Nels age 8 born in WY
Emma age 70 born in England (she is listed as the mother and I assume that she was Charles Philbrick SR mother as the age difference.)
Anna M. Jensen is not listed in this census, and the reason for that is that she appears in the daggett county Utah census, (I assume that she divorced Charles Philbrick SR.)
Daggett County Utah 1820 census
Frank J. Schofield born 1887
Anna M. Schofield born 1883
John C. Philbrick born 1909
1930 Census Sweetwater County
Howard Petre born 1896
Charolette J (Philbrick) Petre born 1905
June C. Petre born 1923 is the daughter
Some other information:
According to the Family History Center:
Anna Jensen married Frank J. Schofield about 1919
Charolette Janet Philbrick born about 1900, which means anywhere from 1900 to 1910 in Echo Summit county Utah (which was also a railroad town) at the time married Nicholas Howard Petre in 1921, he was born 1896 in Echo. According to the information they were married in Echo.
Howard Petre appears in the 1920 census in Sweetwater county his age is 24 and he is a railroad clerk.
This is my own information and knowledge:
Nels Philbrick and his wife Mable never did have any children. Charolette and Howard Petre had 2 children June and a son Dean. Dean lived in Green River. June lived somewhere in Nebraska and had 2 daughters that every so often in the summer would stay with Charolette for a couple of weeks. Dean was several years younger than June.
Good luck with your Philbrick research feel free to email me at email@example.com