When I found the Vendo bone carrier waiting beside Grogor, it was coming from the SW and ran to NW hill. I think the best spot to see the carrier is 43K, 24K and 40K, 21.4K
Mobs are located just north of Haggerfel tower. There is a named Vendo "Scout Grogor" up against the hill in the trees. I stood just to the left of him at Location #43012, 24657 and two (green to a level 6) Vendo Bone-Collectors came from the SW.