I box a pally/druid/warlock and I can say that having that many different classes is a challenge albeit a blast to play. As I play, I notice that I'm rewriting macros as situations change and trying new things to make it easier and to lessen the amount of buttons I'm pushing. If you fine tune your macro's and keybindings to how you want to play I think you'll do just fine. I boxed Kara for the first time last week and it was definitely a challenge. My druid tanked Midnight while my Pally healed. My lock didn't join in until one of our members had to log for the night. Moroes was tough and the only ones standing at the end was my pally, a shaman, and our MT. Madien was a different story. I wrote some macro's that will be mandatory for me for that fight.
Such as
/target Owachi
/castsequence reset=30 Blessing of Sacrifice

and I will have to hoykey my Decursive add-on to my Mangle/Shred macro to clense the debuff she puts out. Just some examples of as the situtation changes, you'll have to adapt your groups macro's to fit the situation. Have fun and Good Luck.

"The IT Monkey" on these boards plays a set up like that. You may want to ask him some tips for that group make up.