Great Census Problem Swap

Do you have someone you can't find in the census?  I do!  Wanna swap problems?

Ordinarily I'm very, very good at finding people in the US censuses and I have found many problem listings for other people.  But, I still have a few of my own Census Problems!  I think new perspectives might help, so I'm starting "The Great Census Problem Swap!" 

We can swap problems for a while and see where it takes us all.  I'll give info on one of my problems.  If you care to spend some time on my problem, just post one of YOUR census problems as a comment and I will work on yours!  I promise to give it my best shot!  

Clara Eveline (Davidson) Porter in the 1900 US Census?
In 1900, Clara was probably recently widowed, her father had just died, and her only daughter had been married in the past year. Clara should be 50-52 years old and probably with her 16-year-old son, L. Willis.  How far could she have gotten?  

Clara was born 24 Jun 1848 in Milton, Chittenden, Vermont, daughter of Titus Davison and Hannah Bascom.  Clara appears to have always used the spelling DAVIDSON, while Titus consistently used DAVISON.  She married Celim Homer Porter 22 Mar 1870 in Colchester, Chittenden, Vermont. 

I have Clara in all of the following censuses:

• 1850 & 1860 in Milton, Chittenden, Vermont with her parents
• 1870 in Colchester, Chittenden, Vermont with Celim and his parents
• 1880 in Woods, Chippewa, Minnesota with SA (Celim), and sons George, Frank, and William (who I believe is also called Roy G.).
• 1910 & 1920 in Los Angeles, Los Angeles, California with son L Willis

But I cannot find her or son L Willis anywhere in the 1900 census.

Daughter Cora May Porter was born 16 December 1881 in Kerkhoven, Swift, Minnesota and son L (Leslie?) Willis Porter was born 28 Mar 1884 in Big Stone, Grant, South Dakota Territory.  However, Willis's birthdate is from a Delayed Birth Certificate filed many years later.  

I believe her husband Celim died 23 March 1898 in Grant, South Dakota, but I only have a family note to that effect.  I do have formal sources for a 1906 probate in Vermont with no mention of a date or place of his death. Clara's father, Titus, died 22 May 1900, in Milton, Chittenden, Vermont. 

Other family in the 1900 census
Son George C. is in St. Anthony precinct, Franklin County, Idaho with his family.  Daughter Cora is in Big Stone Twp, Grant, South Dakota with her new husband.  There is a Frank Porter, 24, single, butcher, living along in Fort Pierre Stanley, South Dakota, but I don't know for sure if this is Clara's son.  There is a Roy G., 23, born Iowa, in the 8th ward, Omaha, Douglas, but I don't know for sure if this is Clara's son.

Two of Clara's three remaining siblings are still in Milton, Chittenden, Vermont for the 1900 census.  The third, Willis A. Davison, is unaccounted for; I think he had left Vermont. 

Possibilities?
At some point, Clara acquired a farm in what is now Bottineau County, North Dakota; the legend is that she won it in a poker game.  There are also family legends that Porterville in California got its name from the family and that son L Willis was a cowboy in Texas before coming to California.  (His first wife was born in Texas.  Their only child was born in 1913 in Los Angeles.)  

Finding Clara or her son L Willis in the 1900 census will probably not give me any earth-shattering new info.  It will just fill in some missing info.

Who is your biggest census problem?  If you care to share, I'll be glad to give it a try!  Have a great day!