You don't need a booster for RAF.
A booster is probably the fastest way to level...
But four toons are leveling, not five.

Without a booster, ie, five new accounts.
All five are leveling, at 3x the speed of five accounts without RAF.
I would recommend having one toon who can tank (Prot Pally or Feral Druid) on the first team.
When they are all 60th...
Continue in Hellfire, as Burning Crusade gear is a huge step up from classic wow gear.
With much better gear, and probably 62nd or so.

You should be able to boost later teams to at least 45th.
ie, The end of Scarlet Monastery.
And then run them through quests etc.
That will get you the most teams to 60+ during RAF.