04.23.2008 author update:
Rio Puerco Road is still rough in spots and its sign has gone missing.
TR56 is a much smoother ride.
The OMG gate is 14.5 miles from Exit 140; 16 miles from Exit 131.
Bonus hike to Fort Red Dog:
From the OMG gate, take the fence road east about 2 miles to a drainage.
Follow it downstream about a quarter-mile. Fort Red Dog is a distinct
reddish-orange formation on the rim. You'll know it when you see it.
There's a cave (tunnel, actually) in an alcove about 200 yards SW of Red Dog.
You might need these coordinates to find it:
WGS84
N35° 11' 34"
W107° 03' 16"
Photos and more details here.
Roads to the OMG and Herrera Mesa
[see map below]
01.03.2010 scouting report:
Rio Puerco Road was pretty well maintained the whole way out. It has some nasty
washboard sections, but other than that it's a lark for any car folks feel like driving.
We came back in past the Canoncito school and that road [T56] was smooth as can
be the whole way.