There are so many counties in Texas that have been ignored by Dems because they are overshadowed by the big metro 5, Harris, Dallas/Tarrant, Bexar, El Paso and Travis. Amarillo by itself is larger than the largest cities of 10 states. Smith Co with Tyler is over 250,000. Corpus, Laredo, Waco, Lubbock, B/CS, Beaumont are examples of what Texas Dems were considering rural. And that older regime was banking on growing Hispanic demographics in those Big 5 to turn Texas blue. But the problem is that for whatever reason (I think partially apathy and partially voter suppression) those huge population centers are not turning out to vote.
For that reason there is a new push towards showing up in those towns/counties of over 250,000. That's about 45 population centers. And while they go into the big metros, not all those people show up, so they need to host events out in the communities, like Plano, Round Rock or Pasadena for instance. Beto was on the right track but like you said about the panhandle, @chainsaw, there is very little organization out in the smaller counties. Hubs like Amarillo, Lubbock, Midland/Odessa are working with some new life, but yes, there's a real need to look at the marginal returns when you get into the counties of say 20,000 or less. Most of those little counties are so backward and red, that Dems feel threatened if they even put out a yard sign, much less try to knock some doors.
TL;DR: Texas Dems are making big efforts to get more presence in population centers that have been overlooked for years. They are hoping the voters in those areas will turn out to vote in numbers that will offset the disappointment in Harris and other counties.
The dem nominee needs to find some strong allies who the people of Houston admire to help them get that vote. They have lost a lot of those old line leaders recently, and Judge Hidalgo has had her issues as well. But whoever the Dem nominees are need several champions in each large center. And not all political, but also generally popular like entertainers and athletes. That area and the golden triangle have lost a lot of votes out of the unions that have gone into the MAGA movement.
Exactly, they are already doing everything they can to suppress the vote, to make it as hard as possible to vote in the big blue cities. Harder to vote when they are under martial law.