Guardsman Sought has multiple quests/objectives. One during the initial game and one during Post-Game.
Note --' It is useful to combine this segment of the quest with A Fortress Besieged as they have the same destination. Monsters and bandits should not prove tough, although wolves, harpies and bandits may cause harm to Adaro as they are attacking in groups. Stay near him at all times when encountering these enemies and attack only those who draw near him, while having your pawn(s) attack the enemy.
The best route to take would be traveling north past the Mountain Waycastle and go through the Ancient Quarry entering via the north side, which would need to be cleared first before accepting this quest, otherwise Adaro will probably not survive this quarry. Following this route will prevent a most likely fatal confrontation for Adaro with the Drake near the Rest Camp, unless the Arisen is skilled enough to slay this enemy first.
This is probably one of the most difficult escort quests in the game. Not only because the traveling distance is long and some monsters may prove tough for both you and Symone, but also due to the fact that Symone doesn't possess much health. Always be wary of Hellhounds, as they can kill Symone easily with 2 (ranged) attacks. Make sure that holy attacks/magic is represented within your party.
Save regularly! This avoids having to walk some distance from the last save point when losing Symone to enemies.
The escort from Cassardis to The Encampment fort is simple, so no explanation needed here. Getting from the fort to the Mountain Waycastle is tricky, since an ambush of Hellhounds and Succubuses is awaiting when passing the Abandoned Storehouse. The best way to get to the waycastle is by moving along the cliffs, so you cannot be ambushed from all directions and to be able to walk around the ambush. From the waycastle to Gran Soren also shouldn't prove difficult. The road from Gran Soren to Windbluff Tower perhaps could be tricky as well, since a mixture of Harpies and Succubuses are found near the Conquest Road, but also a Drake! It doesn't mean per se that the Drake will be close to you when passing the Conquest Road, but always be wary for an encounter with it! Whwnever happening (you'll be notified with a 'slay your enemies' note), run towards Windbluff Tower to have the Drake retreat. The last checkpoint, from Windbluff Tower to Hillfigure Knoll, may prove difficult only if no attention is payed on the surrounding tactics of direwolves. Whenever this happens, let your pawns fight and keep close to Symone, only attacking any enemy getting close to her.
By now, you should've reached Hillfigure Knoll and have helped Symone out with her journey. A cutscene starts to play and the reward is handed over. A job well done!