Going from 300 to 375 is dead easy, but its going to take you as long, if notlonger than it took to go from 1 to 300. Even if your skinning orange mobs,you'll only get a skill up every 5-7 successful skins.
Realistically, you could level up to 375 on the mobs around Hellfire Peninsula,but it's not the most efficient way. The following is what I believe to be amore efficient way to level it up.
301 - 310 Hellboars around Hellfire Citadel in Hellfire Peninsula.
310 - 330 Ravagers around Falcon Watch in Hellfire Peninsula.
330 - 350 Talbuk's and Clefthoofs all over Nagrand. (you could just as easily continueskinning to 375 here if you want, as if wont take that much longer, than goingto Netherstorm and skinning Drakes)
350 - 375 Netherdrakes around Stormspire in Netherstorm or around Netherwing Fields inShadowmoon Valley or Raptors and Wind Serpents around Blades Edge Mountains.