A different type of mounted combat

[Moulson]

So my game has gone....slightly of the rails and now I have a barbarian with essentially a backpack for a goblin (PC as well) to ride in. Now I want to make this as fair as possible so I'm wondering about combat. Im fine with having them take their own initiative to do actions and the Goblin can't move unless they take an action to climb out and an action to move. However what (if any) should the barbarian get for moving? Are there any mounted combat rules that I should look at specifically to make this run better?

[Malk_Content]

Secrets of Magic has this to say:

"RIDING SAPIENT CREATURES
Riding along on a sapient creature that isn’t a
minion requires a lot of coordination and timing.
Both the riding creature and the mount regain
only 2 actions at the start of their turns each
round, as both the mount and the riding creature
interfere with one another’s actions."

And the ancestry guide has this:

"Riding PCs
As a Tiny creature, a sprite PC weighs so little and takes up so little Bulk that it doesn't cause issues to hitch a ride in a sack, shoulder, or other position on another PC. However, the amount of coordination required to ensure you don't get in each other's way or jostle each other into losing actions makes this tactic unfavorable for most fellow adventurers during combat. If you're riding along with another PC or similar non-minion intelligent creature, roll both your initiatives and use the lower of the two results. You act in either order on the same initiative count. While traveling in this way, you each gain two actions at the start of your turn, instead of three, since they spend one action keeping you balanced on their back, and you spend one action maintaining your grip."

[Moulson]

Amazing! Thank you!!!