Tracking Down Robert Henry Collins

I have been researching my great-great grandfather, Robert Henry Collins, for many, many years, but still can't complete a timeline for him. His father died when he was about 4 years old and his mother was left with Robert plus 6 older children. She then married twice more (outliving all her husbands), each time to men with children. And she had 9 children with her second husband (who brought 9 children to their marriage after his first wife died). The families moved around quite a lot during Robert's childhood, living in Texas, Arkansas, and Missouri (at least).
Robert was born in August 1849 in Benton Co., MO. Census records I have for him are as follows:
1850: Alexander township, Benton Co., MO (with parents)
1860: Sulphur Springs township, Benton Co., AR (with mother & stepfather)
1870: NOT FOUND; not living with mother
1880: Montgomery township, Hickory Co., MO (with wife & children)
1900: Joplin, Jasper Co., MO (with 2nd wife & her kids)
1910: NOT FOUND
1920: Collins, St. Clair Co., MO (living alone)
I've spent years reading the local Hickory Co. newpapers trying to track this guy down. His notes that accompanied his subscription payments were often published, indicating that he spent considerably time in Idaho, Oregon and Montana (homesteaded 1910-1914).
Family stories say that after his first wife died in April 1882, Robert dumped his three surviving children and a stepson on various "kin" in Hickory Co., MO, and took off. He resurfaces in Hickory Co. in 1892 when he signs an affidavit for his stepdaughter's pension file, then disappears again. He returns in 1896 and marries a widow with 4 children, with whom he lives until 1902 in Hickory and Jasper counties, Missouri. Starting in 1903 there are intermittent newspaper reports that Robert Collins was living in Weiser, Doniphan, Wood River, Moscow and Hailey, Idaho; Nyssa, Oregon; back in Hickory Co. (1909), and then homesteading near Galata, Toole Co., Montana (1910-1914). He returned to Hailey, ID in 1914 and was living in Camas Co., ID in 1917. By March 1919 he was back in Hickory Co., MO and apparently stayed near his eldest daughter (who lived in Weaubleau, MO; my great-grandmother) until his death in 1924.
I will be heading to Boise, ID in a couple of weeks for a couple of days and am hoping to find mentions of R H Collins in newspapers for the various localities. Hope springs eternal!