Since we didn't have a WRUP this weekend, I'll go ahead and tell you what I did: leveled alts using Alterac Valley. Just a few hours of play, and the levels were flying past without a care, even with only about a 50% win rate. And those times we won fast? Hoo Boy. 100-150k experience for about 10 minutes of work is nothing to sneeze at.
It might be possible that I could have leveled up quicker by loading up a few questing addons and buckling down, but I found PvPing a lot more fun and relaxing for some reason, and I don't think questing would have been all that much quicker.
Anyhow, there are downsides to this method of leveling. You get no gold and you get no gear upgrades. But then again, I have a main who can grab a few hundred gold per day on dailies alone, and with all the honor I'm grabbing, I can just half outfit myself in PvP gear once I hit 80 anyway. So I may just use PvP to gain levels more often.
What about you? Have you been leveling alts via Battlegrounds? What do you think this whole leveling via PvP thing?