As soon as you’re ready to move on to Northrend and trained up as Grand Master. Head to Borean Tundra and hunt the Rhinos, they spawn fast and there is plenty of them. As soon as you are level 400 in skinning you are ready to farm Borean Leather in Sholazar Basin. Almost all mobs here can be skinned, so it won’t be too difficult to reach 425 to train Illustrious Grand Master. But don’t leave the area til you reach level 450 skinning.
Scholazar Basin is probably the best place to farm for Artic Fur, as the whole zone is filled with beast. Do not be discouraged if the farming is slow because the drop rate for Artic Fur is ridiculously low.
See the maps below for where to skin Borean Leather in Wow.
Howling Fjord (350-360)(level 68-71)
1. Shoveltusk, Shoveltusk Calf
2. Plagued Proto-Whelp, Proto-Whelp
3. Prowling Worg, Frosthorn Ram
Borean Tundra (350-360)(level 68-72)
1.Nerub’ar Skitterer, Unliving Swine
3. Coldarra Spellweaver, Coldarra Scalesworn
Grizzly Hills (360- 380) (level 72-74)
1. Tallhorn Stag
2. Grizzly Bear
Sholazar Basin (375- 410)(level 75 -78)
1. Shardhorn Rhino, Longneck Grazer, Dreadsaber
2. Hardknuckle Charger
The Storm Peaks (410-425) (level 79-80)
1. Roaming Jormungar, Ravenous Jormungar
Stay at Nagrand til you reach 350 and train Grand Master and then 385 to move on back to Azeroth.