Hunter: Kresha
Level: 10
Destination: Elwynn Forest
Route Taken: The zepplin outside Orgrimmar to Grom'gol Base Camp in Stranglethorn Vale, north into Duskwood, then ran north across the river to the Spirit Healer at Eastvale Mining Camp. I did this as a ghost (see below).
Alternative Route: From Grom'gol Base Camp, head to the coast and swim north to Westfall. Come on shore then and run north along the edges of the zone. Where the two rivers meet, cross into Elwynn Forest. This is the easier route.
Dangers: If you're doing it the old-fashioned way, expect to die a lot by mobs and Alliance NPCs in both Stranglethorn Vale and Duskwood. The zones are crawling with them, and both are high enough level that sticking to the roads won't help (especially with pats in Duskwood). Also, without Track Undead, it'd be pretty hard to avoid the mobs in Duskwood anyway.
Difficulty level: Medium. You'll probably die in Strangethorn Vale and Duskwood, but you can make it through Westfall pretty easily at this level, if you run like heck.
Testing out a tip from a nice person in the trade chat (this tip is also confirmed at Mania's Arcania), I didn't bother rezzing after getting rapidly murdered by a raptor right outside Grom'gol. Instead, I ran straight through to Eastvale Mining Camp, logged out, logged back in, and rezzed. The bug still works! It felt a bit like cheating though.
The Eastvale NPCs are mostly level 10 or lower, and the area is a very long run from Stormwind and is thus not very heavily populated with any high-level players (at least, not on the four servers I've visited Eastvale on). You might run into a few lowbie players — Kresha got her very first honor point after a level 8 priest tried to take her on — but unless they call for backup, you should be fine. Just make sure your Track Humanoids is on, and you can avoid both NPCs and players fairly easily.
You don't get resurrection sickness at this low of a level, so you'll be fine if you want to die in STV and rez in Elwynn.

If you choose not to ghost run the shortest route, then for a much easier time you could try swimming from outside of Grom'gol Base Camp up to Westfall, then heading through that zone to Elwynn. If you avoid the roads, you'll be fine. You may still aggro some murlocs or crocolisks offshore in Stranglethorn, but you can outrun most of the mobs in Westfall before they kill you. Just bring bandages or health potions.
Eastvale's still a good bet, though. Most of the mobs and other players are lower level than you and it's a ways from Stormwind, so once you've tamed your pet, what better way to try him out than to kill Eastvale mobs until some level ?? Alliance folks come and camp you for 30 minutes, until you have to hide behind a tree and pray they don't find you before you hearth?

This hunter was pretty cool; after I died a couple of times, I emoted my defeat and was left alone. A night elf warrior came around a little later, though, and did a lot of /spitting and "teabagging" and chasing me until I finally managed to hide'n'hearth.