Consolidating the Info for quick reference:
1) Added this rectangle to the North Desert of Ro map: (cut/paste in the map file obv.)
L 2471.6265, -5968.8740, 21.3325, 1013.2996, -5985.0645, 29.9773, 240, 0, 0
L 1013.2996, -5985.0645, 29.9773, 1013.2996, -6915.5938, 26.7216, 240, 0, 0
L 1013.2996, -6915.5938, 26.7216, 2437.3682, -6931.4453, 34.0639, 240, 0, 0
L 2437.3682, -6931.4453, 34.0639, 2459.3113, -5966.0234, 21.9323, 240, 0, 0
2) Cleared the (see below) mobs aggressively in the rectangle area. When killed, the (see below) mobs are replaced with different mobs types (e.g., young gila monsters, jackal's, etc.) which you leave alone and continue to hunt only the mobs on the list below. (note: unknown if this list is complete but it worked...)
a sand scarab
a dune tarantula
a shriveled mummy
a madman
a crypt mummy
an orc raider
a large rattlesnake
a parched zombie
a brown asp
a puma
3) Stood at 6504, -1510, 79 and picked off the (see above) mobs from the top of the hill until Dunedigger popped about 3 hours later. (note: Brewall map had approx location noted)
Thanks to those who posted prior for the source reference information.