Getting taurens to orc starting points

[Watto44]

I would call the 'practical limit' 55.

I would have to agree. Although your healing would be very handy, the NPCs in AV are ridiculously powerful. The last time I was in AV I was level 57-58 and the sentinals/mountaineers were knocking me about pretty hard (even in bear form) and took me forever to kill one-on-one. (Oh, and a slight nit-pick: you need to be exalted with frostwolf clan to get the mount, not revered. Bummer, I know. :( )

That's not to say don't go in, just be careful of the NPCs. (Particularly if you're rushing the Stonehearth GY.) On the plus side: as well as the lovely rep rewards for the quests, you get a very tasty 6.6k xp reward for them.

As for getting to the Valley of Trials, I would probably wait until level 5. The quests should still be green, and those few extra levels might make getting from Camp T to XR that much easier. :)