Warning about Rental Vehicles:
Most vehicle rental agreements restrict vehicles to paved roads. Check your contract and be aware that the rental company can charge you for damage to the vehicle outside of the contract agreement specifications.

AAA and other towing insurance may not be valid on backcountry dirt roads. Typical towing charges in the area of Big Bend National Park range from $250 to $1000 dollars or more. Most rental sedans have a small “donut” spare tire and should be driven only on paved roads and short maintained dirt roads, while most rental 4WD and all-wheel-drive SUV’s (sport utility vehicles) are equipped with standard street tires rather than truck tires. On high clearance 2WD and rougher 4WD roads these tires are more susceptible to tire puncture and multiple flat tires.

Be sure that your rental vehicle has a good spare tire, that the tire is accessible and not “locked” into a keyed holder, and that the tools to change the tire, including jacks and wrenches, are in the vehicle and accessible.