Hmm you may want to try Buburimu Peninsula that seem to be a simmilar lvl zone as dunes. To get there you have to go seblina and then take a boat (stay below deck pirates may attack as well as sea horrors). I've seen grp there while camping leeches for my damn summoner ruby and that zone has less people but seems like a good zone.
Hit up the lower areas of Ghelsba, Giddeus, and Palb dungeons. Farm for the dungeon keys. By the time you get them all, head back to Jeuno, and do the Khazam airship quest, you should be just about right for Khazam.
Excellent suggestion Sprits! I like Bubu, except that on my server it's always under beastman control, so no crystals. Still a nice alternative to the Dunes, especially for us Windurstians.