To get to Navajo Springs take Interstate 40 east from
Holbrook, Arizona. Exit at Navajo (Exit 325), which is
about 39 miles east of Holbrook and 14 miles east of the
Petrified Forest exit. Take the paved road south, across
the railroad tracks and the Puerco River. After 2-4 miles
(I'm sorry I don't have exact mileages here and the roads are
too new to show on any maps I could find) take the road that
heads east to Navajo Springs. In a mile or so you'll see
the small Indian community of Navajo Springs on the north side
of the road. There is a dirt road leaving the eastern edge
of this community that goes north a mile or two the historic
site.
Keep in in mind that the Navajo Nation requires a permit for
off-highway travel on the reservation. Here's where you
can get a free permit for casual travel: