If I understand your original post correctly:
. . .through Texas on I-10
you have been around several of the distinctly different regions of our great state: the upper Gulf coast, the upper south plains, the Hill country, the Big Bend region and the cities of Beaumont, Houston, San Antonio. But, as you know, sticking to the interstates is almost like going through a long, open tunnel.
The regions you have missed (if only on I-10) would include the Piney Woods region of Deep East Texas and Northeast Texas, which, of course, we who live here think is the best and most beautiful, especially in the Springtime. We have two national forests: Sam Houston and Davy Crockett, each with many good places to "camp." We have some of the best state parks in the system: Sam Houston, Lake Livingston, and further north (think Tyler, Texarkana) Tyler State Park, Daingerfield State Park, and some really nice COE parks on our lakes, such as Lake 'o the Pines.
Just west of the Pine Belt is the area most of us call, "North Texas" which is centered around Dallas. This is part of a larger region referred to as "Lakes and Prairies." Then heading on up northwest past Wichita Falls and Childress, one enters the great Panhandle of Texas.
You have far better experience of Texas (speaking of following I-10) than the many people who have said to me, "Yes, I've been to Texas when I went West along I-40." They, of course, have seen only one small and untypical region of Texas, the Panhandle.
There are far too many variations of routes across Texas east to west to include in this small space, but two regions are worth a real visit in the Springtime: Northeast Texas (around Tyler) and the Hill Country (around Fredericksburg.) A route could be planned that would include both.
This is more than I set out to post, but if I can help with any more specific questions I'll be glad to respond.
EDIT to note: Serious omission in my post, the Mid Gulf Coast and the Lower Rio Grande Valley.-- probably more, but these were serious omissions.
