The Legend of Curly's Meat

You initially find out about the Legend of Curly's meat by reading the book on it in Doc Alice's House in The Town of Boring Springs:

The book tells the story of a legendary treasure -- a massive chest full of premium Meat, secreted (in the 'hidden' sense, not in the 'extruded' sense) in the Western desert by an old cowhand named Curly Butterfield.

Finding the treasure requires you have opened up all 3 map sections (east, west, and coast).

Solution

1. Find the map in Butterfield Ranch (outhouse).
2. Get Curly's compass from Kole Ridge Mine (Deeper in the Mine, need a shovel).
3. The compass directions lead you to Alexandria Ranch. Inspect the compass again there to follow it to the secret area.
4. Dig up Curly's auto-gyrotheodolite. (Requires 50 Muscle)
5. Head to Madness Maw Mine, third level, and use the auto-gyrotheodolite to reveal Curly's Cave. Inside you'll find the left half of Curly's map.
6. Read the map to find out that Halloway has the other half.
7. Using a needle and your Lockpickin' Expertise, get Halloway's pin from a bunkhouse footlocker in Breadwood.
8. Go to Halloway's Hideaway and return his pin. Then ask him about the map. He'll provide the right half of Curly's map.
9. Examine the right half to assemble the treasure map. The treasure is in Halloway's Hideaway! Fortunately you're right there, so dig it up at the spot marked X.
10. Open up Curly's strongbox.

Note: If you ask Hab Halloway about his pickaxe before the silver pin he will not give you the right half of the map.