His journal is in his secret underground lab. You can get the key by taking the Secret Message to the Mill, and opening the fountain plaque using the Cosmic Symbols (press all three and the Sun).
It is missing a page, and you will need to reach the Princess tower at the castle in order to look for it (it is under Mordred's bed). All it gives you is the coordinates to the Pewter Moon (X-56 Y 52).
(see related question)
mordred's missing journal is in his study. his missing page is under his bed.
you push through
You go into Mordreds lab and grab a paper and turn it into her.
The Missing Journal Page tells you where you're going, but you need a spaceship to get there. The saucer Excalibur is crashed out in the mud past the Mill. (see related questions)
find the coordinates to the moon under mordreds bedA pop. winner
There is still a missing page you may need. To find it, tie the rope to a big arrow at the castle crossbow. Shoot up and left to hit the door to the Princess tower. With the note from there, you can look under Mordred's bed at the Museum.
You do not get or use a bucket on Astro Knights Island.
There is no treasure chest on Astro Knights Island.
It is under the bed in the place where you have to pay with the golden coin.
buba dizzle
There are no bird eggs in astro knights island.
The key unlocks mordreds secret lab. You can get there by seperating the two hay bales.