Id go with something like a DRZ 400 if you think you'll spend at least half your riding off pavement or rarely above around 65 mph.
If you think you'll spend most time on pavement, like 60 or 70 percent, then I'd get something more comfortable for highway speeds.
Of course, the compromise of performance vs value vs versatility is the question here. I could ride a pure street bike on most Tx dirt roads but it wouldn't perform that well. I could also ride my plated dirt bike for 500 miles on the highway at 70, but it wouldn't be fun. You can buy a budget friendly compromise bike like a KLR 650 that will do both but not be high performance in either or you can buy an expensive, higher maintenance and performance bike like a KTM 790R which will do both with high performance, but at a cost.
I feel like the T700 really fits the bill for most of what you can do in Texas without getting to pricey. Seems like a pretty good compromise bike like you were saying.
Do you think a DRZ400 with some wind protection and either wide ratio or higher gearing would be a little more pleasant on the pavement?