While I'm just starting a 5 box pve team myself, I can't give you advice from experience, but I also think I have a good idea on how to go about it. I plan to start doing instances as early as RFC Plus learning all the instances at the end just seems daunting. and a lot of the early ones dont' have heroic versions, so you will have simply missed that content all together. I want to do EVERY instance while I level up. There were lots I never really did as I'm a self proclaimed "pvp guy", but now I'm going full force pve w/ this team. If you are worried about gearing, just do instances that are slightly below your level. You'll still get some nice blue gear better then your quest greens from instances you might be say... 5 levels too high for? I would start with running instances just a little below your level to get a feel for it. From then it's just trial and error I think make sure you have pve specs for you guys too. If I was handed your team, I would do the hellfire area, get all the quest greens I can, then hit up Ramparts and see how it goes! Plus after you got Hellfire quest greens you could do some level 60 content with ease I would guess because of how good outlands greens are compaired to old 60 gear. Sorry for wall of text, hope this helps!