Hi, fernly--
I've passed through Sonora, and visited the Sonora Caverns, but it was a long time ago (nearing a quarter-century, in fact), and my memories are kinda fuzzy. Sonora is to the west of Kerrville, which is in the heart of the Texas Hill Country--pretty, hilly (bien sur!), and often quite green, with lots of juniper (aka mountain cedar) in the area. Going west past Kerrville, you're starting to get into terrain more typical of western Texas--arid, often quite flat, with sparse or desert-like vegetation. I remember Sonora and Ozona (another town not far from Sonora) being more like this. My memory of my visit to the Caverns is pretty hazy, apart from having been there--I remember at one point in the tour, our guide turned off all electric light (perhaps just a flashlight she was carrying?) in the chamber we were in, to let us sample total darkness, and I thought I would freak out if the experience lasted one minute longer.
Tell you what, my sister (with whom I live) and our mother (who is visiting us this week) were on that visit, and I'll check with them to glean their memories and impressions of the place. I'll post back here after I've heard what they have to say.
Until later,
Scott