As has been mentioned previously, when the McClains moved from Albany to Tallman, the Tallman farm apparently came with a job—that of collecting cream from area farmers for the Albany Creamery. (I don’t know how that worked legally.) Here we have (Uncle) Bernard and (Grandpa) Arthur McClain on the cream route, collecting cream around 1924. You who were scandalized before to see a photo of Uncle Bernard in overalls, prepare to be scandalized again. ;–)

The scale on the back of the truck and the device in Grandpa’s left hand (which appears to be used to test the cream in some fashion) suggest that the cream was bought by the creamery on a weight basis or something similar rather than by simple volume—and furthermore that part of Grandpa’s job in collecting the cream was to record weight and other measurements at the time of collection.
One of the cans in the back of the truck appears to have “A.C.A Albany” painted on it. I take A.C.A. to be an abbreviation of “Albany Creamery Association” or some similar name.
The sign displayed on the back of the truck cab reads (I think) “Of course I’m going to the Linn County Fair, Albany, Oregon, Sept. 3·4·5·6 [dates are partially obscured, but these seem most likely]” This is interesting for several reasons. First, the presence of the sign provides some idea the time of year when this photo was taken (summer). Second, if the dates read as I think they do, and if the fair ran from Wednesday to Saturday as it does now, the dates tell us this photo was taken in 1924. Third, at some point in the last 100 years the dates of the Linn County Fair moved from September to July. In fact, I believe now all county fairs in Oregon are scheduled well before the end of August because the State Fair is held in early September (and the results of the county fairs determine what exhibits are sent to the State Fair).
Technology that arrived in Albany in the late 1920s made cream collection obsolete. When the condensery came to town, it became possible for farmers to sell their milk whole, without separating the cream, which eliminated the need for collection of cream separate from milk.
Mom (Florence McClain) records that the last vehicle Grandpa used for the cream route before it was discontinued was “a wooden bed in the back of a roadster, which was more comfortable for the family to ride in.” Evidently, then, the truck used for the cream route was the only vehicle the McClain family had, and was used for family transportation as well. Since the truck in the photo above is clearly not the roadster Mom mentions, this photo must have been taken at least a few years before the cream route ended. This is consistent with the likely date given for this photo.