I would personally put the Paladin into the group, since you want the team leveled more then leveling the warrior.

This gets you one toon who can skip every collection, and has done a bunch of other quests already (probably the majority of the quests the team will attempt).

Queue for AV as often as you can stand it.
Paladin will not be in your bracket, so you'd mount up.
And fly straight up on him/her.
And be there, when the PvP ends.
PvP is free experience for your team.
Run them all to a bunker/tower and stay there until it burns; towers and Belinda/Galv are your leveling exp.

Definitely do a lot of instances on the way up.
The tanks gear level, is the largest factor in how easy/hard instance are.
As an 80th, you will outgear almost everything, until the end of the leveling stage.
Even then, normals as an 80th, are all doable.

Mix it up, quest, instance and battleground.
Don't let anything get stale/boring/old.
It might help to have a totally unrelated team, for the odd hour or two play session.