My ear tells me some country seems to lean on the major pentatonic scale.
Add a flat 3rd between the 2nd and 3rd and flat 5th between the 4th and 5th for a little chromaticism.
In D it'd look like this
g---------------7---
d----------7-8-9----
a---5-7-8-9---------
the 8's are the added notes for the chromo feel.