There should be a wiki out there for powerleveling with a 70 in instances.
Powerleveling just instances with same lvl group.
Leveling by quests only.
Leveling by quest/instances.

I can't really give any help here i just started. Got my guys to 36 last night and here is what i have done:
1-8 quest
8-15 RFC
15-19 SFK
19-24 RFK
24-29 SM lib
29-40 SM Cath (Can probably do ZF at 37, planning to stay till 40 but staying in sm cloth. Maybe when i get the first done and tailoring done i might do ZF earlier then 40. Would like to stay till 40 because it will be a long walk.)