Every hiker wants to cross the Grand Canyon. Just because it is there.
I did a similar trip across the much deeper Colca Canyon in Peru. Very challenging and very rewarding.
But to cross rim-to-rim takes advance planning. Of 30,000+ requests for backcountry permits each year, the park issues only 13,000.
Ideally, you should book at least 4 months in advance. Transportation can be a hassle. Details on besthike.com Kaibab Trail
This is why we need besthike.com — to get a heads-up on which of the great hikes require advance planning.
The best time to walk rim-to-rim is Spring and Fall. Summer is hot! Also, the North Rim facilities and road access close during the winter.
The second best hike in the Grand Canyon is a loop from the South Rim. Logistics are much easier. But hike rim-to-rim 20.6mi (33.2km), 3-days, 2-nights if you can.