When playing 2 different classes like this I like to choose some keys I dont normally use on my main, like the numberpad keys, and bind these keys to some things the follower can do on command. THe druid would have his 0 to + keys bound to the number pad keys. They would all be macros like

/assist focus
/cast Moonfire

or

/target focus
/cast Rejuvinate

This way I can play my main normally, then hit the numberpad for those helper abilities. I also have the tilde key as a /follow focus macro because that gets broken a lot. THen all these keys can get sent to both wows, but they might not do anything on your main, just the helper. Focus could be your pet, or a tank if you ever play with someone else.

But thats just how I do it, everyone has quite different setups and preferences!

Kille