Spoilers if anyone is still wondering:
Talk to little mo in lumbridge to start the quest. He's right in front of the bridge by the castle.
The first package location (man near a bunch of trees) is in karamja, west of the banana trees. Just follow alongside the water and you'll find a Man npc carrying a walking stick and a backpack close to the water. Just talk to him and return to lumbridge and search mo's cart for your next clue.
The second location (guard in a high place) is at the very top of the jail next to port sarim. Climb the ladders to the top and find the only guard there. Talk to him, return to lumbridge and search mo's cart for the final clue.
This one might take you a minute. Bank all your stuff and head to the wilderness! The third guy you're looking for is William the team cape salesman and he'll be carrying his huge sack of capes all over the north end of red/lava dragon isle. He usually wanders between the red spiders hill (slightly north of the lava maze) and the demonic ruins. He walks constantly so you have to really comb the area. Members can use the lever in edgeville to teleport there quickly. After you find him, return to Mo and claim your reward. (as well as a very interesting foreshadowing story)
