I've done some similar research but my focus was in Sudan and about a decade earlier. It seems that aid operations and daily activities differ greatly with locations (war zone or mountains etc), jobs (WFP pilot, Water & Sanitation coordinator, nurse, etc), and aid agencies (UNICEF, MSF, or missionary groups like
WHI.)
Food distribution can be very varied. Check out these UN photos:
World Food Programme aircraft is dropping food
Following an air-drop of food
Nurse checks registration cards to issue cereals (non air-drop)
Baby is being given oral rehydration solution
One goofy thing was at first I assumed these agencies would rent a hotel room for a VIP on field visit. I later realized at that time, Juba, the biggest city in Southern Sudan, didn't have any hotel (after 40+ years of civil war.) Tents were the only option. There are now many new, crazily-expensive hotels but most aid workers still live in tents or sometimes mud huts.
Many of these aid workers have written blogs, often very informative and can serve as a contact point for a potential interview. Various aid operations also provide reports and invaluable photos. These are good starters.
AFAIK, NGO personnel are not armed. Big operations like
OLS may organize their own security teams (I assume with consent from local government--if there is one.) When UN peacekeepers are involved, I bet they also serve the aid workers. In extreme cases they may even hire local warlords to provide security (see
technical trucks and Afghanistan news.) But once in a while you'll read in the news aid workers being kidnapped or even killed. These are not the safest jobs in the world. These people deserve a lot of respect.