I'm boosting a lot of chars myself atm.
got 3 accounts full but most only level 66 atm

I did ramps up to 63, then got to around 66 in settrek halls or mana tombs.
Keep your alts at max range, like almost a full room behind due to the mind control totems or you could prolly just macro a /tar totem
/cast frostbolt or something
But I just kept max range.
Mana tombs is nice for the quests in there and I also went there for the enchanting fortitude on boots recipe for leveling enchanting, try to keep the pulls small if you got a lot of priests in the group, they heal a lot.

http://www.dual-boxing.com/wiki/inde...tance_Boosting
Not sure if I should go shadowlabs, botanica or shattered halls next.