We are flying into LV in late March and then traveling by rental car to San Diego via I-15 with one overnight stop in Barstow. If we fill our gas tank before leaving LV and are renting a small SUV, should we be okay on gas until we get to Barstow? Someone who lives in AZ told me that opportunities to buy gas are few and far between in that area, and I am concerned about running out of gas. We are also planning on taking a detour between LV and Barstow into Mojave National Preserve. Is there a gas station there? I don't mean to sound naive, but this person from AZ said that they knew someone who ran out of gas along I-15 twice, and that concerns me, unless of course it was just a case of poor planning on that person's part.