It works. I've been using the method Ualaa laid out. On my 3rd team with a druid booster. Takes about 30 hours to go from 11 to 80, purely dungeon boosting. Tack on another hour for 1-11. Could probably do it a little faster, depends how motivated you are.

I level all 5 to 11(11 to get in SFK), then insert an 85 druid for boosting. Auto-run, swipe, and +30% run speed is pretty nice. Cat form until HoL @ 75. I prefer dungeons where I don't have to move at all or only a few times.

Now that I think about it, 11-60 only takes about 10 hours. Slows down a lot after that. 70-75 is no fun. 75-80, HoL is a breeze.

Here is how I go about it.

1-11 quest

11-21ish SFK (Leave toons at the zone in)

21-42 SM Armory + Cath (Leave toons @ zone in, anything before first steps going up to Herod, you get xp. Anything past those steps, pull down for xp. Pull Mograine out to edge of waterfall, kill everyone there for xp. Some places like Scholo might be better after say 35, but I usually just stick it out here. Throw in Library too if you're hitting the instance cap/hr.)

42-48 BRD (So many areas to pick from, great xp. Will have to move your toons a few times, or just tow them)

48-58 LBRS + UBRS (Seriously good xp here. For LBRS, the 1st bridge-overlook area you come to where you see ogres standing on the other overlook to the right, just park your toons there and you'll get full xp for the whole place. UBRS, gotta move the group a few times.)

58-63 Ramparts(leave @ entrance) + Blood Furnace once or twice(on follow)

63-70 Sethekk Halls (On follow until room with first boss, then leave them there)

70-72 Nexus or Utgarde Keep (toons on follow)

72-75 Violet Hold (small instance, but move toons to a corner away from entrance...you'll see what I mean)

75-80 Halls of Lightning (toons on follow)