The Google map and GPS coordinates for ORNL's Visitor Center are: 35°55'52.7"N 84°18'37.5"W. More maps are available for Getting to ... proceed straight past the traffic light to the ORNL east vehicle ...
Both Google Maps and Apple Maps are accurate & provide reasonable arrival times and similar routes for driving. Google Maps offers more detailed traffic and hazard information compared to Apple Maps.
But do not forget that Google Maps also has a very good mode is Driving Mode that many people do not know. Driving mode not only alerts you when there are traffic jams, directions to the nearest gas ...