Some tips to consider in the game:
When you are sending search party, keep in mind that the larger the party, the better of them having to find stuff. Have at least one with higher fighting skill in your search party to lessen the chances of casualties. Always aim for areas in the map where there are chances of getting multiple items.
In area 3, try to search places where you will find machine guns and grenade launcher. Make sure to have at least 4 members in a search party for higher chances of getting a find even if it means having no one to defend the house but you. Once you have the a machine gun and grenade launcher, assign a personal assistant so that you will have someone to reload your grenade launcher.
For the complete Dead Zed 2 walkthrough showing full gameplay see the player below.