Lots of property crime like vehicle breakins in the city, be alert.
One time I went to a Spurs game. Armed guards at McDonald's. The environment felt a lot like the Los Angeles Coloseum in the 80's where you would park on the guy's front lawn in the hood, and pay him to guard your car when going to the concert.
Back on topic, go to the Alamo (during the week if possible) when it opens, and then check out the river walk. Do happy hour at the tower, I think it makes the elevator ride to the top free. Pay to park in a safe spot. Those 3 sights aren't too far from each other.
Tower of the Americas is a 750 foot tall tourist attraction located in San Antonio. Featuring an observation deck, revolving Chart House restaurant, & 4D theater ride.
www.toweroftheamericas.com
For fast, but good Mexican food, Taco Tote right off I-10. Plenty of safe parking in this area. Pico de Gallo and Mi Tierra are touristy but good. Parking can be difficult on weekends. Henry's Puffy Tacos on the south side of town, excellent. The Taco Garage over by the airport, north side had homemade chips last time I was there.
If you are going to be NE of SAT, there are good but busy BBQ joints in Luling and Lockhart. The I-35 between SAT and Austin sucks. I have been hit by truckers retread tires twice on that fwy, and a woman got killed by a flying tire on I-35.
When you see a buc-ees you must stop, get gas, and use the bathroom. I think it's the state law in Texas.
Traffic is terrible, like every city. Hopefully you are staying outside the 410 loop, or better outside the 1604 loop. Austin probably not worth the visit, very dirty, homeless, and the once fun nightlife now has pride parades marching down 6th St. Carry on.