Talk to the Reinforcement to start him moving. He will follow you where ever you go, so try to avoid aggro.
The NPC tends to run away. Before running, he will always say something like "Huh? Was that an enemy scout?!", "I am worried about the soldiers back at the garrison. I have to see if they are all right".
The person he is currently following should keep eye contact. It's best to run ahead a few yalms then turn around, and repeat this. Obstructions and terrain elevation sometimes make this difficult. Keep your cursor on him at all times, so you won't waste time targeting.
To get him back to following you, just click on him again.
Talk to the NPC at the stronghold to end the escort.
The Reinforcement NPC does not get aggro from any mobs.
Only one group can do this Campaign Ops at a time (i.e. only one reinforcement NPC per zone) so you may have to wait for another group to finish. In this case the Gate Sentry will say "The troops you are to guide to the stronghold have not arrived yet. Please wait a little longer."
Reinforcement knights have been dispatched to assist in the defense of our nation's strongholds. You are to travel to a northern garrison under San d'Orian control, and escort the awaiting knight to his final destination. Unit Requirement: 1-6 members