I looked your family up in the Ancestry census records.Robert and family moved North.
In 1910, the family is in Hanaford precinct, Lewis County Washington.I cannot view the actual image because of a mixed up link, so I cannot see the details.
In 1920, he is still in the same place and that census record I can view.He is listed as Robert W Allen 59 (immigrated 1880, natualized 1899, born Ireland, Farmer, owns his farm. Wife is listed as Bolen D.(?), 48 born Sweden. children are listed as: Katherine 21, b CA Bula 20 b CA (this is the one your listed as Viola, but I looked at 1900 and I think it says Buela) Robert E 18 b CA Walter J 16 b CA Harold 13 b CA Mildred 11 b WA Verna 5 b WA Mildred and Verna are listed as born Washington so the family must have moved there between 1907 and 1909.
In 1930, the family has moved to Portland Oregon. Robert W Allen 67, owns, (value $8000) born North Ireland, occupation is listed as none. Wife Dora H 59, children Katherine M 31, Buelah D 31, Robert E 28, Walter J 27, Verna C 15.
We are not related, but with 10 children that are probably spread across three states, there should be plenty of descendents.Hopefully one of them is looking for their family too.