Puscilla

When you get the quest for Puscilla, she is NOT in the cave below the dot. (This is Houndmaster's cave.) To get to her, take the ramp to your left and go up a level, she'll be up inside a cave complex. The actual entrance is 65.6. 26.9, above.

Start at 61.7, 26.9 "Defiled Path" head northwest up the path.
59.6, 28.1 the path curves right.
60.1, 26.1 cross the bridge,
Turn right at 64.7, 32.2 and cross the bridge.
Go straight inside the cave and up to the top.

Beriberi's coords for Tomtom:

/way Antoran Wastes 65.6 26.9 Entrance
/way Antoran Wastes 64.7 32.2 Cross bridge
/way Antoran Wastes 60.1 26.1 Cross bridge
/way Antoran Wastes 59.6 28.1 Turn right
/way Antoran Wastes 61.7 26.9 "Defiled Path"

The rares who drop these mounts only yield loot for you once per day. I have created a macro to track whether they have been killed by you during this reset:

/run for k,v in pairs({Hound=48821,Blistermaw=49183,Vraxthul=48810,Puscilla=48809,Skreeg=48721,Wrangler=48695}) do print(format("%s: %s", k, C_QuestLog.IsQuestFlaggedCompleted(v) and "\124cFFFF0000Completed\124r" or "\124cFF00FF00Not Completed\124r")) end

The macro tracks the following rares (since they drop similar mounts):

[npc=127288] who drops [item=152790] found in Antoran Wastes at 63.1 25.3
Blistermaw who drops [item=152905] found in Antoran Wastes at 61.8 37.3
[npc=126199] who drops [item=152903] found in Antoran Wastes at 53.2 35.8
Puscilla who also drops [item=152903] found in Antoran Wastes at 65.5 26.7
[npc=126912] who drops [item=152904] found in Eredath at 49.6 10.0
[npc=126852] who drops [item=152814] found in Eredath at 55.7 59.8