Our family of four took a month-long trip across the US in our RV last fall! Homeschooled my 5 and 8 year-old boys along the way. Their favorite stop was the National Cowboy and Western Heritage Museum in Oklahoma City. Absolutely wonderful and it captivated even my youngest! I can understand wanting to hit the southern end of Texas to see Carlsbad Caverns. However, we went to the Luray Caverns in Virginia and my husband liked them better than Carlsbad! I've never been to Carlsbad Caverns, so I can't compare. He said Carlsbad was definitely bigger but Luray was more up-close and intimate with the formations.

Luray - got it! I didn't know about them. We have been to the Cowboy and Western Heritage Museum and our boys loved it too. They liked dressing up as cowboys and building with the huge lincoln logs. Plus, "The End of the Trail" is breathtaking. Thanks for the suggestions!