Now with nearly the whole of your army across the great river, you hear rumors that the Roman General Scipio's army has arrived by way of fleet at the mouth of the Rhone. Do you?

Scout only. Send five hundred Numidian horsemen to pinpoint the Roman army's location.
Scout and Mislead. Send the same five hundred Numidian horsemen, but give specific instructions that if they engage the enemy, to lure them to the old Carthaginian bank on the west side of the Rhone - where several of your forces still have yet to clear out, thereby tricking Scipio into thinking you have not crossed the river.
Prepare for defense. With the Roman army nearby, batten down for battle and prepare for an attack.

Next.