I prefer to boost this way.
10-20 Shadowfang keep
20-35 Scarlet monistary
35-45 Sunken Temple
45-60 Scholomance.

Much less running around. Also all these instances are on the same continent so no going back and fourth. Last time I ground this out, it took about 12-13h of played time RAFing with a 80 paladin and 4 shaman that just sat there. Also you never have to move your slaves, they will get full xp by just standing at the entrance to these zones.

You dont need any special tank gear for your paladin. Seal of light, blessing of sanctuary, and reckoning talent is all you need. You wont ever have to heal or wait for mana as long as you pull massive mobs. Just go buy a stack of saronite from the AH and have someone pound out 5 shields for you. Just destroy them when they break, its not worth repairing as making new ones are 100x cheaper.