Thank you.

One Christmas Eve morning, there was a gleam in his eye,
Today was the day he would find that fat guy.

His sister would help him, along with his cat,
Together they’d trek, they vowed to not spat.

Off to the pole, which resided just north,
They’d attempt reach he who gave presents thus forth.

So they gathered their gear, and warm winters coats,
Leaving their farm, and passing their goats.

Their cat trailed beside them, along for the ride,
Guiding them past where they should not reside.

Down the old road, at a break-neck pace,
They would finish, they would win this race.

The snow slowed them down, though not a whole lot,
They would soon reach, where there minds had so sought.

 

"They’d attempt reach he who gave presents thus forth."

is bit advanced of a sentence for a children's story. It's very clunky in general.
 

I'm not a skilled rhymer, but as a reader, I don't like couplets that had to be written a certain way just to make them rhyme. That's the impression I got from the "spat" and "goats" lines.

I wish I had a copy of Cat in the Hat. Anyway, it was vibrant and funny and engaging. Good source of inspiration?

You might name your characters.

Why does the boy want to find Santa? Why does his sister agree to help? That's engaging. I care less about the scenery (although it's worth showing.)

We know how the boy and the girl in Cat in the Hat felt. It was too cold to go out and too wet to play ball; they had to sit in the house and do nothing at all.

With good motivation, I think this could be an engaging story too. And although you might keep the couplets all the way through, an occasional break might be OK for emphasis?