It is recommended that you get some silent oils or a mage with sneak. There are quadavs that are easy prey and decent challenge to a level 60.

The merchants are being held at a jail cell located at (I-8) in Beadeaux. To get to the jail from the entrance to Beadeaux, take the left path at the first fork and take the tunnel down at (H-7). If you don't have Cursna, take a right on the first fork and examine The Mute to get silenced. Then head to (M-8) past The Afflictor, which would curse you if you weren't silenced (bring an Echo Drops if you need it). Before you go to the jail you need to collect Quadav Charm from De'Vyu Headhunter, a lvl 45 NM, which spawns around (I-9) and (I-10). After getting the Quadav Charm go to the jail at (I-8), watch the cutscene to get a key item "Trader's Sack" and return to Thunder Hawk to get a reward.