You have to go to Linus (by the mailbox) and he will send his letter to the Great Pumpkin. If you have the Pen from his house, go left and play the football scene with Lucy and Charlie Brown. You can then use the football at Snoopy's doghouse to get the flying goggles and start the Red Baron scenes.
you wait for the great pumpkin!
look at the comic peanuts
the blanket ends up in the pile of leaves
There is no pigeon on great pumpkin island.
The pumpkin patch is to the right on Great Pumpkin Island. It was the only area shown in the island preview.
Click on the leaf pile, then wave your cursor back and forth to sweep the leaves away.
you help the boy with the blanket roll the pumpkin to his home
up my bum
There are no buildings or upper rooms on Great Pumpkin Island.
uncover the leaves after he jumps in the leaves
The name of the island is Great Pumpkin Island. See the related question below.
To find Linus's missing blanket, just sweep your mouse cursor over the pile and the leaves will be blown away.