South Texas includes San Antonio. It also includes the Rio Grande Valley along the border with Mexico and its cities (Brownsville, Harlingen, McAllen).
I moved to Texas immediately after completing an LVN program in Van Nuys. I took NCLEX in Texas, and found a job the day after receiving my temporary license.
Pay rates are tied to the cost of living. Rents and house prices are significantly cheaper here than in CA. My utility bill averages about $70 monthly for a 1,900 square foot house. My basic phone service is $24.99 per month, not including surcharges and taxes. My water/sewage/trash bill averages about $40 monthly for all 3 combined. My house was built in 2004 and cost $100k in 2005, and is probably worth $90k today.
The pay is lower here, but your money will take you farther. The Mid-Cities area is rather family-friendly, has affordable rents, and good school districts (Birdville, HEB). This area sits right in the middle of Fort Worth and Dallas, and includes the suburbs of Euless, Hurst, Bedford, and North Richland Hills. My friend's mother rents a 1-bedroom apartment in Hurst for $490 per month. My friend's house in North Richland Hills cost $109,000. We all do fine on our LVN pay. This wouldn't happen in California.
Arlington is a city of about 360,000 people located right between Dallas and Fort Worth, and is a little more diverse than the Mid-Cities.