Don't have a lot of time so I can't post a proper trip report, but Justin and I spent several days in Del Rio about a year ago, including a visit to Seminole Canyon. We took the rock art tour and had a terrific time -- the volunteer guide from
The Rock Art Foundation was a superb speaker and thoroughly knowledgeable. He also was terrific about engaging the children on the tour, and they in turn peppered him with all sorts of terrific questions about the peoples' who created the rock art, what they were thinking and trying to communicate, their lives and stories, etc. Terrific time, and terrific close-up views of the various rock art that's still preserved in the area.
I'll try to post more when I find my notes from the trip. It never made it to WildTexas.com in the form of a trip report, sadly.