Official information
http://npmaps.com/grand-canyon/
https://www.nationalparks.org/connect/blog/grand-canyon-rim-rim-hike
Lodging
https://www.grandcanyonforever.com/
http://kaibablodge.com/
Personal Experiences:
https://www.rimtorim.org/hike-it/
https://www.earthtrekkers.com/grand-canyon-rim-to-rim-hike-planning-guide/