Since it has been a few days with no responses, I'll at least give some thoughts to the locations.

* LeRoy & Lewis: not terribly far from the airport (probably an easy cab/Uber ride), a little south of downtown.
* La Barbecue: a little east of downtown, and also not far from the airport (also an easy cab/Uber ride). Close to Lady Bird Lake / Town Lake.

* InterStellar: I drive right by there about every week (on my way home from the lake), sometimes on both Sat and Sun mornings. There are always people waiting to get in (sometimes I pass by before it opens), and the location causes some traffic around that intersection. It is a suburban area, typical unassuming strip mall. The 45 minutes from the airport is probably accurate...but as we all know, if there is traffic, that could be an hour or more. You'd probably have to use toll roads for at least part of that trip (or add another 10-15 minutes). I can't see there being much nearby from a tourist standpoint. Maybe if you are going to or from the lake (Lake Travis, possibly Austin, depending where), you could stop by.
I would say it could make a nice stop on the way to/fr Marble Falls, but if your trip is soon, the primary road/bridge through hasn't yet been rebuilt (mid/late Sep is the current estimate). The bridge was washed out with the big July 4 weekend rain, and the detours take you a bit out of the way. But you could make it on your way back from Fredericksburg (and one of those detours).

That said, let me know if you would like other ideas of things to do in the area. I work near downtown and it would be great to see you again while you're here. Perhaps we could organize another Do.

Oh, and if you are planning to see bats... I'd suggest Round Rock: https://www.batsinroundrock.com/