I have used my 70 lock to boost all my groups. SM I just run none stop casting Siphon Life and Corruption on each mob, lifetap while running. ZF same thing. I run with Succy on defense with soul link off. I again pretty much go non stop to the room with all the scarabs, SoC them down, then run out and reset. Siphon life and corruption is enough to kill the mobs and the succy chases down the runners. SM I'm usually waiting on the "Too many Instances" so it is a fast way to boost.

RFC 8-10
WC 10-20
SM 20-44-45ish
ZF 44-48
Quest in all areas as fast as possible to 55.
55-58 Ramps

This is the way I did the shamans and currently doing my lock team. The lock team however I'm using 2 trial accounts to get them to 20 quick via RAF.