Why not Real?
335 - this is mostly in Edwards Co - the Real Section is mostly rockless and very wooded - I've hunted here quite a bit . . . lots of Bairdi, lots of Alligator Lizards, Lots of Slimy Salamanders - honestly, I think its too wet and too shaded for alterna . . . the local collector I know around here (he's into hots) has also never found Lepidus there
337 - between Leakey and Camp Wood - leps are there, as are bairdi and alligator lizards, so far no Salamanders . . . but I still think these slopes are way too shaded for alterna, but its your best bet for the county
The difference between Real and Uvalde is the amount of tree cover - Real is pretty darn cedar-choked and Uvalde is mostly rocky hillsides covered in Purple Sage - more like Val Verde County south of the 377/277 junction - which is still fairly marginal
Sliecher - As I recall, the canyons peter out right about the Sutton Co line - most of Sliecher Co is high grassland (the divide country) - great habitat for Milks and Many-lined skinks, but (unless its on private land) I haven't seen any alterna habitat there
Until someone puts a specimen in my hands, I view the Telegraph possibilities as extremely slight.
Honestly, the only Counties that I would expect to find alterna where they haven't yet are as follows:
Uvalde (right along 55)
Otero Co, NM - north of Del City
One other consideration for your list . . . Mike Forstner supposedly caught a suboc on 277 in Dimmitt Co near Carrizo Springs . . . just a thought.
The funny thing about all of this speculation is that folks often look out their backyards and think "this looks like alterna habitat" and wonder why they aren't there (I've heard "why not Big Springs . . . Why not San Antonio . . . etc) but one thing we have to recognize is that there are barriers to their dispersal out there - my opinion is that somewhere it gets too forested, the outcrops and ground get too wet during the winter, and/or, the ground gets to where its not fractured enough.
I think that where I'm at right now is too wet in the winter (I've got Slimy Salamanders) for alterna . . . I think somewhere in Uvalde Co, we loose rock fracture and/or it gets too wet again (Plethodon at Garner).
Troy