Since you've posted the same inquiry on many mailing lists, I'm providing search findings for other than just Stevens County. Perhaps this will give you a jump start for other names in the family:
In 1900, Grace was living in Spring Valley, Stevens County, WA, census enumerated on 21 July 1900. The actual census image showed the family:
Milo Runyon, 46, April 1854, born in Kentucky to both parents born in KY, miner, married 20 years.
Jane, born Apr 1854 in Iowa to father born in Germany, mother in Indiana, mother of ten children, all living:
John, May 1887, North Dakota
Edna, Aug 1885, ND
GRACE, July 1886 (1886 as identified on the census page), ND
Robert, May 1889, South Dakota
Roy, Oct 1891, Washington
Dilliard, Dec 1894, WA
"Herold" (as spelled), Apr 1900, WA.
The Washington Birth Index has the following births:
"Ruser Ruser", born 2 March 1911 in Ferry County to "Orillis F Ruser" and Grace G. Runyon
Dillard Carlton Rush, born 4 Nov 1915 to Orillis Francis Rush and Grace G Runyon
Harold Milo Rush, born 2 Mar 1900 in Ferry County to "O Willis Frances Rush" and Grace Gennieve Runyon. (Since the 1900 US Census was enumerated in July 1900, the birth date of this Harold must be in error. Also, the middle name of Milo reflects the first name of Grace's father).
I noted you had Grace returning through San Francisco from Guam.
The actual image shows Grace Rush, age 63, born in North Dakota, returning with Avery Bascom Rush, Fallon, Nebraska, age 46, born in Deer Trail, Washington. He carried one footlocker, one box and seven handbags. They were on the ship "General Henry W. Butner".
--The 1930 census for Klamath Falls, Klamath, OR, the image shows this Avery as a son. Family living on 211 Windling Street.
Orville F, age 58, born Kansas to father born in Illinois, mother in Missouri, a laborer in a saw mill, married at age 27.
Grace G. age 43, married at 15
Avery B, age 26, Divorced, born in WA, laborer in saw mill
Harold M, 24, born in Idaho (The birth date would fall 1905/1906, but the place of birth of Idaho does not agree with the birth record in Washington)
Lewis E, 20, born in Oregon
Charles L, 10, born in California
Milton W, 6, born in Oregon
Michael A, Grandson, age 4 1/12, born in CA to father born in Kansas, mother in Ohio
Patrick D, grandson, 5/12, born CA, to father born KS, mother OH.
--The 1920 Census for Portland, Multnomah Co, Oregon, had the family living at 323 17th Street N., renting
"Orvillis R. T" or "R. F" (As shown in the census), age 45, driver for Auto Express, born in Kansas
Grace G, 32, born ND
Avery 16, born WA
Doris, daughter, born Idaho, 14
Harold, 8, born in WA (This confirms the WA Birth)
Charles 8/12, born Oregon
The 1910 Census has an interesting "finding" for Orin, Stevens County, WA
Avery, age 6, born in Washington, father born in Kansas, mother in Colorado
Doris, age 4, born in WA, father in Kansas, mother in Colorado.
both are of the correct age, and father being born in Kansas. BUT, they are listed as Grandchildren of a Susan McClung, 88, widowed born in Tennessee, and children of a Harry Rusch, age 34, married six years, born in Kansas.
---Also in 1910 for Arden, Stevens County,
Avery Rusch, age 6, born in Washington, father in Kansas, mother in "US"
living as a nephew of J.T. Donavon, age 51, born in Canada and Mollie Donavon, age 52 born in Kansas.
----The Avery "Rusch" could be just an enumerator spelling mistake, but the Avery and Doris, with the right age is something to look at for confirmation or later elimination.
The World War I Draft Registration shows a "O'Rillie Francis Rush", born 16 Feb 1873, living in Skamania County, Washington. This could be "O. R. F. Rush"
--Interesting note: there was a John Milo Runyon born 1 May 1879 living in Skamania in the WWI Draft Card Image database. He was married to Susie A. Runyon
California Death Index shows Grace died on 23 Dec 1963 in Nevada. This means she probably died in Nevada and the death certificate was performed in California. She could have died near the boarder and just transported across the state line; or, there may be another Death certificate in Nevada as well...it happens. Her mothers maiden name was 'Bradspri", which is probably shortened by database size or method from a longer name, "Bradspring/Broadspring...??" Grace's Birth date was shown as 30 July 1887, which is one year in difference from the 1900 Census. The census is often wrong either by enumerator mistake in math, or understanding, or the family gave the wrong year. But, Death Index are often wrong also, only a birth certificate from North Dakota could identify any error.
The Oregon Death Index identified an "Orillis Rush", death on 25 November 1932 in Josephine County, Certifcate 133, Spouse name was Grace.
The 1870 US Census for Cedar, Johnson County, Iowa
John Runyon, age 37, farmer and Blacksmith, born Kentucky
E.J. 36, born Kentucky
David E 17, Kentucky
MILO B. age 16, born in Kentucky
Mary E. 13, Iowa
Ida 9 Iowa
Emma 4 Iowa
Silas W 2
In the 1910 Census for Boise, Ada County, Idaho, Milo B. Runyon, a mine promoter was living in the home of a Henrietta E. Bell as a Lodger, he was listed as 61 and widowed, born in Kentucky.
-----Robert G, brother to Grace------
In the WWI Draft Registration Card images, Robert G. Runyon, born May 8, 1889 in Port (Fort?) Buford, North Dakota. He was a Stock buyer living in Hunters, WA living with a wife and Wife's parents.
---Fort Buford is in Williams County, ND:http://www.rootsweb.com/~ndwillia/
------Dillard Carlton, brother to Grace------
WWI Draft Registration Card: Dillard was born December 12, 1895 in "Turk", Washington. He was working for Milton Bowen in Hunters. He supported his mother.
-------Roy K, brother to Grace---------
WWI Draft Registration Card: Roy was born Oct 14, 1892 in Davenport, WA. He was a locomotive fireman on the Railroad, living at 2101 Malon, in Spokane.