After leveling from 60-62.5 in Hellfire Ramparts I can say that I am completely burnt out of that instance. I never was able to kill the last boss but I have come to the acceptance that Outland instances are not designed for a 5-boxer and there will be some encounters that are simply too challenging for me to beat at the appropriate level. For a regular group the fight wouldn't be nearly so hard but with my setup I can't effectively avoid fire spits and his front cone AoE attack.
At 62.5 I decided I couldn't take anymore Hellfire Ramparts so I decided to go questing. I ran over to Zangarmarsh and started doing every non-collection quest available. Doing that, I was able to bring in the rest of level 62 and hit 63 plus some. Hellfire Peninsula had a lot of collection quests but luckily Zangarmarsh has very few which is very nice for 5-boxing. I think I'm going to finish up all non-collection quests in Zangarmarsh and then head off to Hellfire Blood Furnace until level 64 at which point I will hit Coilfang Slave Pens.
One of the nice things about Burning Crusade is that there is a new instance at every level and the creatures in the instances are within 3 levels of each other. I have found that I level the fastest when I'm at the top end of the level range for an instance so now that I'm 63 I get a new instance every level which should help keep things interesting and keep the amount of disenchanted loot to a minimum. (http://www.wowwiki.com/Instances_by_Level)
I will probably take a break from instance grinding to do all the non-collection quests in each zone as well but due to running around with 5 grouped characters, I don't expect to be able to level off of non-collection quests alone. Instances are also better xp/minute though they can become quite repetitive.
On the macro/control front I respecced my Paladin to Protection/Retribution and my shaman to Restoration/Enhancement. I was finding that with my Paladin being the leader I needed someone else to be healer because anytime I was healing meant that was time I couldn't also be moving all my characters around. Now the shaman is the healer and when in-combat his follow-macro doesn't work. This means that my shaman will follow me into battle and start swinging but I can move the other 4 characters around freely without interrupting his heals. I do have an in-combat follow macro bound elsewhere so I can move him back into the fight where necessary but for the most part he stands still and heals/swings wherever he lands. With this new setup I am killing slower (only 2 real damage dealing classes) but I have found that my overall efficiency has gone up because I wipe less now and I can handle more pulls with less setup then I could before.
My quest to level 5 World of Warcraft characters at the same time.