Now what the route will look like from SH-130 to Bastrop, I don't really know. I am guessing an 85% freeway, meaning there will still be side roads and driveways, but the building for frontage roads for the grade separated sections would minimize those. They need to just freeway the whole thing.
If TX DOT at least gets flanking frontage roads built alongside TX-71 from Toll-130 to Bastrop that would at least preserve the ROW for a complete freeway upgrade.
I think expanding he right-of-way to the south is the way to go. There is all sorts of crap on the north side of the highway, but just some dilapidated barns on the south. I love your comment about Ellinger being a blink. It may be small, but with them forcing you to go 55 (dropping from a cool 75) and all the people pulling in and out of Hruska's Bakery, its kinda a pain to drive through.
A single freeway exit for FM-2503 (in front of Hruška's) would solve that problem. The speed zone would be eliminated. It would dramatically improve the safety levels for thru traffic. If TX-71 was 100% Interstate quality from TX-130 to I-10 it might improve business in towns along the corridor like Ellinger. Right now it doesn't look like much. A complete freeway could encourage new development.
As much as I don't like the US-290 corridor and find it to be a waste to be the link between Houston and Austin, I am not opposed to upgrading it to an interstate. I just want both SH-71 and US-290 to be upgraded to interstates. If US-290 west of Austin is upgraded to an interstate for it to tie to I-10 west, then that will leave only US-290 existing between Austin and Houston (if a west interstate is built, you know US-290 will be truncated)
The US-290 corridor definitely needs to be upgraded to Interstate standards going West out of Austin, thru Johnson City & Fredericksburg, ultimately with a freeway connecting to I-10. Austin is a big enough city in its own right (city limits population near or just over 1 million) to justify an East-West Interstate thru the metro. US-290 is the only West side outlet. US-290 and TX-71 are the East side outlet, both pointing towards different halves of the giant Houston metro.
Austin is one of very few US cities with million-ish city limits populations that doesn't have both North-South and East-West Interstate highways. NYC, LA, Chicago, Houston, Philadelphia, San Diego, San Antonio and Dallas all have North-South and East-West Interstate corridors connecting to them. Austin just has a North-South route (I-35). San Jose is the only other exception.
Technically I-80 is San Jose's Eastern outlet, but that's way to the North. I-580 is the nearest East-West Interstate. CA-152 is the nearest East-West highway to the South. San Jose is blocked in by big mountain ranges, preventing any direct East-West corridor to San Jose from being built. US-101 is the only Southern outlet. Even though US-101 badly needs to be brought fully up to Interstate standards from San Jose to LA it will be many years before it finally gets there. Anyway, Austin doesn't have any of those geographical challenges in building a new Interstate. But it is building up more of the California style political challenges.