I have also heard that missives aren't the best way to go.
Since you're already in Veskal's, why not just play in Jade Depths? I was able to successfully solo there (including Spinthra, the first named) as a 10 cleric. As you level, you can move further down and pick up more named... There are several decent loot drops there, including a belt from the second named that I'm still wearing at almost-18. (Not that I'm much good at the equipment game, so that might not mean much.
Any time you run out of quests, moving to a new location is an option. Three Rivers on the far side of Leth Nurae is good, as mentioned before... Or you can follow the path to the east (pick it up just south of Veskal's) and there's a little campout place where you can do the troll quests, among others. Mobs in the 12-13 level range, as I recall.