Glossary of Aviation Terms used in the Post:
IFR --
Instrument
Flight
Rules, eg. flying by using the aircraft's instruments only, rather than referring to visual references outside the aircraft. Pilots with an IFR rating can fly in conditions (cloudy/overcast days; light rain; high fog, etc.) that would keep a non-IFR rated pilot on the ground.
Since we had some low clouds in the area, Justin flew an IFR approach to the Gillispie County Airport (Fredericksburg) and we then flew to Enchanted Rock using Visual Flight Rules -- "eyes outside the cockpit", due to no clouds in the area and a low altitude of flight.
VOR --
Very High Frequency
Omni-Directional
Range -- a primary form of radio navigation for pilots.