She decided to carry it in front.

There was a good-sized rock near, upon which she stepped, leading Sage King alongside; and after an exceedingly trying moment she got up, holding the pack.

For a wonder Sage King behaved well.
Then she started off, holding the pack across her lap, and she tried the King's several gaits to see which one would lend itself more comfortably to the task before her.

The trouble was that Sage King had no slow gait, even his walk was fast.

And Lucy was compelled to hold him into that.