This is a guide I wrote for the World of Warcraft TBC Classic addon Guidelime for levelling from 60 to 70 through dungeons as a group avoiding any outside questing. Hopefully it can be of use to someone else. Feel free to modify it. The whole folder needs to go into your WoW Interface\AddOns\ folder (outside the Guidelime addon folder)
Unfortunately, the guide only works as Alliance.
Progression overview:
Grind Hellfire Citadel until honored Do Hellfire Ramparts and Blood Furnace Quests
Do the three Party quests from Cenarion Refuge Grind Slave Pens and Underbog until honored Turn in Quests
Go to Shattrath and go Scryer/Aldor
Do Mana Tombs until honored
Do Auchenai Crypts until honored
Do Sethekk Halls until level 68
Go to Karazhan starting attunement
Do Shadow Labyrinth
Do Steamvault
Get key to the Arcatraz
Do Arcatraz
Do Old Hillsbrad Foothills
Do Black Morass
Get Karazhan Key