I usually quest to 10th (with the high level destroying everything, so mainly just 3x quest exp's).
Then instance:
Deadmines... Stockades... Scarlet Monastery... The troll instance near Gadget... Stratholme... Ramparts.

A dozen hours of /played time sounds about right.
Especially if you have a toon at each place, capable of RAF summoning.




For 60 to 70, you can Boost in Borean Tundra.
Not sure how quickly 4 toons boost, but 2 is very fast with Shaman's at 80 to boost with.

Totems are considered pets, so if the group does any damage at all (tag), pets can do 99% and the group gets the full kill exp's.
For this to work, it needs to be a group.
With a group of 2, 60th to 70th was approximately 11-12 hours of play time.
But that allows 3x Magma Totems for the kills and 3x Stoneclaw on round-robin for keeping the lowbies alive.
A party of 4 lowbies, would mean 1x Magma and 1x Stoneclaw, a huge reduction in kill speed and probably much smaller pulls.
I'm guessing a group of 2 twice, with large pulls.... or a group of 4 once, with smaller pulls.. would both be approximately double the time.

I ran 3x 80th Shaman's. And grouped a Mage + Druid.
The Mage spammed Arcane Explosion and ran from one group of rhino's (3-5 mobs) to another group of similar size.
One of the shammies would Earth Shield the mage. Mage was wearing full +STA greens.
Then drop Stoneclaw x1 and Magma x3. And refresh Stoneclaw if it was taken out.

Incidently, I made a ton off of rhino meat, for the Dalaran cooking daily, sold it in stacks of 4 or 5 (whatever the quest wanted).