"As I learn more of the Faith and the dragon, I feel I must be growing stronger... Still, I haven't yet the courage to travel far on my own. I know I've asked much of you already, but would you travel with me a while?"
Escort Quina from Cassardis to the Prayer Falls, situated to the West of the Abbey. It is best to avoid attempting this quest at nighttime because the area near the Prayer Falls will be guarded by Ogres. And, since Ogres get easily excited by female members, it will be twice as hard to protect Quina.
First off, as with most escorts, running ahead will leave the NPC you're escorting way in the dust and vulnerable to baddies along the way.
Aim yourself to the north and go through the (if not now then soon) familiar winding mountain pass between Cassardis and Gran Soren. At a fairly leisurely pace you can make it to Gran Soren by late afternoon. Even though the Inn is expensive, spend the money to sleep until morning, you've still got a fairly long walk ahead of you. It wouldn't do to find yourself in the middle of an unknown wood at dusk or beyond.
Use the Northwest (NW) exit from Gran Soren. This allows you to sprint through the city without tiring AND when you exit Quina will be right next to you again without having to wait. Furthermore, you'll likely avoid at least one band of armed bandits who are usually encamped in the ruins surrounding the capital.
Proceed along the road and at the bridge, take a left and head almost directly west. Your pawns will likely tell you how unsafe it is running through wilderness, but they're not really that smart anyway. Aside from some outcroppings of rock, you're almost dead on to the Abby. You'll skirt the south side of the Abby and find the falls fairly easily.
One caveat, I have (on occasion) found a cyclopse wandering the grasslands between Gran Soren and the forest. As they are really large, these should be fairly easy to avoid.