Why, do you think, do the creatures have a tough day ahead of them?

The grop has a hard day ahead of them because they are preparing to leave the hilltop.

The Ladybird, who was obviously a kind and gentle creature, came over and stood beside him. ‘In case you don’t know it,’ she said, ‘we are about to depart for ever from the top of this ghastly hill that we‘ve all been living on for so long. We are about to roll away inside this great big beautiful peach to a land of… of… of… to a land of–’
‘Of what?’ asked James.
‘Never you mind,’ said the Ladybird. ‘But nothing could be worse than this desolate hilltop and those two repulsive aunts of yours –’