We obviously got a lot of help from existing sources for doing challenge modes. Much of the order of pulling I describe will be from the AFTERMATH Gold Challenge Mode Guides. Extremely helpful! My goal is to give you a perspective more from the healer and what kind of damage to expect/cooldowns and other things.
Update (October 17th, 2013): I stopped writing challenge mode guides because I felt like I did not remember them well enough to give a good rendition of what worked for my group. Soon I will be doing challenge modes on a ranged DPS character and hopefully through that process will remember much of how I did them on a Holy Paladin. In the meantime, you can find almost all you need to know as a healer and what to expect in challenge modes from my ‘Introduction’ page.