The Official Monster Hunter 3 Ultimate Topic

Why the pineapple did I not see the Desert Warfare quest before.

Ok, now I got the quest to take on Jenny (Jhen). Does anyone have any advice, any good weapons or armor I need?

Any weapon with Ice element. The Barioth lance, Sabertooth, worked wonders for me. Also gem in Artillery Expert and eat a meal of Meat + Dairy and choose Steam as the cooking type to get Felyne Bombardier. Artillery Expert and Felyne Bombardier will both boost damage on the dragonship's Ballista/Cannons, and they stack.

As for armor, just anything you can get Artillery Expert on. I used Agnaktor U since I was using a Lance.

Using this setup, eventually I was getting to sub-20 minute kills.

Also, break both of the cracked spots on his back, and keep attacking them afterwards (This is the weakest point you'll be able to hit reliably in the first phase).

Make sure you use up all of your Ballista ammo and Cannon ammo, it makes a very noticeable difference.