Pokémon B/W. How's the adventure going so far?

[Chaoxys]

I need to get the national pokedex before I can trade over my Raikou for Zoroark right?

No. You know that big city where the 3rd gym is? This one guy there will ask for a password (I don't remember it), and if you tell him it, he will allow you to trade over event based pokemon from the older games.

Ah, did that little bit last night, thanks.
For those who have Zoroark, does he just appear randomly after you transfer a shiny dog?

Nope. Go to the route to the left of the town with the 4th gym. You will see a backpacker you can battle. Go past him and oyu will find a path into the woods. If you go in without the dogs you will find a trailer with a silent woman inside and a trainer who will talk to you. Go in with the a dog and get ready for an amusing message, followed by a battle.