With changes in National Forest boundaries, and proposals for an enlarged Havasupai Reservation and a Grand Canyon National Park, the teens of the XXth century could be called pivotal in the swing away from the tentativeness of the previous decades. So this GLO map of 1912 is an excellent base:
Here are some noteworthy features, starting in the northwest. Two sections of the Dixie National Forest had been proclaimed. They only lasted a decade, though the upper right was trimmed to be the Mt. Trumbull section of the Kaibab NF. In the 1970's, it was dissolved into the surrounding Arizona Strip BLM lands, and some of it became a wilderness. The other Dixie lands ended up, mostly, in Lake Mead NRA; and later, some, but not enough, in Grand Canyon National Park.
The Kaibab National Forest at this time had been made the Kaibab Plateau. Later it was put under the Tusayan administration in Williams, all renamed the Kaibab NF. Too bad; a unified regional adminstration of the Arizona Strip public lands would have made lots of sense over the years.
There were a number of changes in the Forest boundaries, and the Navajo lands would be moved west toward the Colorado.
The GCNM boundary is the dotted line.
The Havasupai Reservation is misnamed as the "Yavapai", and it is easy to see how all those townships of the Tusayan NF south of it could have been natural additions.
Hualapai lands look intact, but the struggle to wrest half of them from the Santa Fe was only nearing its beginning.
And here is what that ASHPS Park proposal of 1910 looks like (compare with terrain map on Dec 28 entry):