Hi Nadine, I'm not related to the Jackson or McPeak family but it sounded like you were looking for more info about them.
I first found Roswell and Ellen's family in the 1900 Chetco, Curry Co., OR Census. Roswell, b. Dec 1851, OH, marr 23 yrs, farmer; Ellen, b. May 1860, CA, had given birth to 10 children who were all alive in 1900; Henry J., b. March 1882, OR, farm laborer; Alfred, b. March 1884, OK, farm laborer; Andrew J. Jackson, b. June 1886, OR; Sarah L., b. May 1888, OR; Gonwa [Geneva?] M., b. April 1890, OR; James, b. Feb, 1892, CA; Chester, b. May 1894, OR; Annie M. b. Oct 1896, OR and Leora b. July 1898, OR.
They will still living in Chetco in 1920 but Ellen must have died before that Census. Roswell, b. abt. 1855, OH, general farmer; Elmer, b. OR, 30, single, no occupation listed; Henry, b. OR, 28, single, laborer home farm; Alfred, b. OR, 26, laborer home farm; Andrew, b. OR, 24, laborer home farm; Genioca [Geneva?], dau, b. OR, 20, single, James, b. CA, 18; Chester, b. OR, 16; Anna b. OR, 14; Leora, b. OR, 12; and ARthur b. OR, 8.
I found another Geneva M Jackson in Klamath, Del Norte Co., CA, b. OR, 20, single, hotel cook. May or may not be your same Geneva.
Roswell Jackson of Curry Co. d. 6 Sept. 1915 per death cert #5084. Source: OR Death Index 1903-1998.
In 1920 Anna, her husband, child and brother Elmer were living in Portland, Multnomah Co., OR. Frank S. McPeak, head household, b. NE, 35, caulker shipyard; Anna McPeak, b. OR, 23; Dorothy E., McPeak, b. OR, 11/12ths and Elmer W. Jackson, brother law, b. OR, 39, single timber faller logging camp.
Also in in 1920 the rest of the Jackson children were living in Chetco. Alfred, head, b. OR, 35, single, farmer; James, b. OR, 28, single, brakeman locomotive; Chester, b. OR, 25, single, farmer; Leora, b. OR 21; Arthur, b. OR, 18, logger lumber camp; and Louise Smith, boarder.
In 1920 A. J. [Andrew] Jackson and family were also living in Chetco. Andrew, b. OR, 35, logger lumber camp; Kathleen, b. IA, 39; and Calvin b. CA, 4.
In 1930 Andrew Jackson & family were still living in Chetco. Andrew, marr @ 27, b. OR, 42, dairy farmer; Kate, m @ 33, b. OR, 47; Melvin Jackson, son, b. OR 15 and Ray C. Hill, boarder, b. CO.
It looks like the McPeaks intersected once with the Jackson family [Anna]. Successful Hunting!