Sweetheart of the Rodeo, released in 68, is generally tagged as the first "country-rock" album, but it was in fact a fairly straight country and western album, the fact that it was done by the Byrds giving it the rock slant. But in fact, several bands were already at work on the country-rock amalgam, with much more of the sound that later became identified with that genre.
Parsons had already done Safe at Home with the International Submarine Band, but this effort too was more of a country album than country-rock. Fact is, except for a few songs with the Burritos, like Devil in Disguise and Lazy Day, Gram was a devotee of honky tonk and gospel country styles and never strayed far from them.
Gene Clark was carving out a country-rock sound with the Dillards before Sweetheart, although he met with little commercial success. Clarence White released an album with Nashville West that is very much a country-rock album, in 1967. This cut from 67, a cover of a Waylon Jennings song, is closer to country-rock as it would be known, than anything on Sweetheart.