FINDING ROCKHOPPER!!!!!!!
On this page, there's a guide on how to find Rockhopper!!!
First, you gotta check if he’s online or not. Type in his username in the log in screen and type in a random password (at least five digits long). It will say he’s banned if he’s offline. It will say ‘Incorrect password’ if he’s online. If he’s offline, stop and try again later.
Alright, finding Rockhopper. That’s something just about every penguin out there wants to do (If they haven’t found him already). You can talk to him and you can get a free background!
For one thing, Rockhopper is Club Penguin’s account, he can be a bot or a real person (depending on the time of day). So that means he can be on any server, in any place he wants to be. However, sometimes he likes to go on these servers a lot: Mammoth, Frozen, Mittens, Rocky Road, and any highly populated Servers (the ones on the left column of the first page of the U.S. servers list, for example). But nowadays, he can be on any server!
Now, finding him is kinda tough, but it can be done. Two helpful factors are: that he’s slightly larger than the average penguin (he’s bigger, thus easier to spot if you’re in the same room as him). And there’s always a flood of penguins around him (they’re usually all red). And one surefire way of knowing he’s in a room is that you can’t get into the room because its full and there’s hundreds of penguins clobbering to get into the room. Also, he moves around the rooms in Club Penguin every so often if he’s on the Server. For example, he might appear in the Ship Hold, then move to the Beach, then the Town, then the Iceberg, etc. But sometimes he stays for a very short (or long) time in one or two rooms and switches servers.

And he’s most likely to be in the Dock, the Beach, the Iceberg, the Pizza Parlor, the Plaza, and (if his ship gets rebuilt) his ship, The Migrator Basically, rooms that have a large penguin capacity, unlike the Mountain Top which can only hold around 20+ penguins before its full.
As for times he’s on, he’s most usually on during peak hours (times when everyone’s on), or he can also be on during random times of the day and night when there’s a moderate amount of people or no people at all.

Once you find him, its awesome! There’s about two dozen penguins there asking him questions and HE ANSWERS THEM (with a pirate accent). Also, you get a free Rockhopper autographed background You can’t buddy him. (you can put him on your ignore list if you want), you can go to his “home” (The Migrator is his home. Update: DON’T CLICK FOR HIS SHIP. Since the Migrator sunk, you won’t go there, you will just loose connection), and you can send him postcards and I hear he sometimes sends one back! And you can follow him around when he walks around Club Penguin. Sometimes he screams "Pirate Parade!" and that gives you a chance to get a once in a lifetime screenshot of just you and him standing somewhere.
Here's a picture: