While Texas is often considered in a league all her own, much of that comes from self-description, istm, & stems in great part from pride of having been a nation on her own for those few years. Still, the sympathies found amongst multi-generational Texans here in the western counties have traditionally been with the South. The "western" influence came more from the fact that this area contained vast expanses of ranchland and the Old Mexican influence of the traditional vaquero (much of which is still obvious, even today, in the rural areas).
When I was growing up (more decades ago than I want to think about - I'm gettin' old!), the term "yankee" was still a denigrative epithet verbalized with considerable disgust. I remember a couple from Maine who moved in here back in the 40s and stayed. Took a really long time for the locals to stop looking sideways at them and stop treating them as "other". Sad maybe, but true. This was not the case with those who came in from the "acceptable region" of the U.S. (The South.)
I'm just sayin'...
Penny