Bill Lorenz of the International Organisation for Migration (IOM) is keeping a diary for the BBC News website as he helps thousands of Sudanese trek home to Raga in the south-west, following a deal to end a 21-year war.

He is transporting the most vulnerable on trucks through forests and swamps in a race against time, as the heavy July rains are due.

Frustrations abound on all sides. No food drop again.

We hoped people from the UN mission for South Sudan would bring a WFP monitor by helicopter today. But now, it seems it's a bit more complicated than we thought.

The mission is supposed to be monitoring the peace in southern Sudan and can't always get involved in humanitarian operations. Without a monitor, WFP cannot do the airdrop no matter how much it wants to.

People have been waiting to return home for years

Explain all this to people who have no food.

I know a lot of people without food. Around me now, behind me on the road, and among the cutters ahead. The situation is serious but I have to stay optimistic.

The peacekeepers want to meet Commissioner Resiki, the SPLM commander leading the group. We suggest they come meet him and when they do, they bring the WFP monitor.

If it works, the airdrop could be tomorrow or Saturday. People would then have enough rations to get to Deim Zubeir.

New clothes

We are now at a new camp - Rede - 10km from our last transit camp. We will all stay here until the food comes. People are arriving all the time, driven by the promise of food.

Even the cutters return to the camp each night instead of pushing on as they have always done.

Yesterday I noticed a brand new pair of shoes under some plastic sheeting where a family was camping. It surprised me. The group is poorer than those that stayed behind in their homes.

But people want to return with their heads held high. I'm told everyone has packed new clothes and shoes so when they arrive in Deim Zubeir, they will look nice.

Even Howiya, our cook, who only has two changes of clothing on this journey, has a new outfit for the occasion.

Souvenir

Commissioner Resiki told me during our walk to this camp afterwards that they may be economically disadvantaged now, but people in this community will be influential when they return. Their history with the SPLM will have benefits.

Dr Aden tells me now another woman is in labour and will give birth very soon. There have been several births in the past few days.

Trek in pictures

Yesterday he delivered a premature baby boy safely and the day before, identical twin girls. Although everyone is fine, the mothers' milk is taking a long time to come.

It's the lack of food, exhaustion and stress of the journey taking its toll. So Aden is giving the women glucose until the milk comes and the babies suckle properly.

I can hear Howiya's two-and-a-half-year-old daughter, Hayat, crying. She has the funniest expressions. When we first met, she was very quiet.

But I've got very fond of her and I suppose I have spoiled her. She's the only person I've noticed who has gained weight. It must be all the biscuits I've given her over the months.

We are now 70km away from Deim Zubeir. The problem ahead of us is water. Or the lack of it.

People are cleaning fuel drums and then filling them with water. The drums are then taken to the front to support the cutting teams. But that won't be possible for everyone and certainly not after we leave here.

As a distraction from all the concerns, I have bought a python skin from a man called Bishara.

He'd caught it, killed it and eaten it. Now he is selling the skin - for $25. The skin is 3.5m long and about 14 inches in circumference. I wanted a reminder of this journey - as if I could ever forget

Below, Bill answers some questions sent in by BBC News website readers.

Omer in New Zealand asks about the security situation.

There has only been one real security incident so far on this journey. Two of the IOM staff, Andrew and Abbas met members of a former militia who were following the group.

They had turned to poaching now they had lost support from the Sudanese government. They were carrying several elephant tusks. They were looking for food.

Commissioner Resiki and his security team, told them to take another route and not to follow us. There are several security men who travel with the group - they monitor the route and walk among the people. Luckily, the group is large enough to discourage any problems.

Any incidents among the community itself have been handled very effectively by Resiki. There is a security element within the community. Impromptu jails are set up where people are kept for a day or so. I would say, in general, security has been good.

Patty Flynn in the US asks if the children realize the significance of the trip.

I think so yes. Yesterday when I was walking with some of the IDPs, I saw a girl, about 7-8 years old. She was carrying this heavy load on her head. She was just getting on with it.

It has struck me that the children are mature. I don't hear complaints, like about not having food. Everyone understands the significance of this trip.

It is not just about going home but what a change of government means for them. It means their inclusion in the country. Before, people in the south felt marginalised. There was a total lack of development. Now they see the moment as an opportunity for change.

Wol A Wol in the US asks what is being done for other Sudanese refugees across Africa.

To get refugees back, it has to be a joint collaboration between the Sudanese government, the governments of the countries where the refugees are and the UNHCR. They will agree on when and how refugees go home. I am travelling with a group of internally displaced people and there is a different assistance given to IDPs.

Sami in the US asks how Bill feels, as he will be able to return to a "normal" life, whereas many of those he has been travelling with have gone through terrible experiences and lost relatives in the war. How do you walk away from these people you have experienced life and death situations with?

I don't have family to go back to in Nairobi where I work. Everyone is in the US. These people I am travelling with are achieving a dream of establishing a semi-autonomous southern Sudan.

They are travelling with part or all of their family. And they will meet up with rest of family in Deim Zubeir. There will be lots of family reunifications - everyone will be so overwhelmed. Of course there will be gratitude for our help, but in general, I think it will be natural for people to just say good-bye and move on.

Start their lives again and create a new future. Me, I am looking forward to returning to Nairobi.

Michael in Kenya asks why more trucks are not being used and whether it wouldn't have been better to wait until the situation had improved.

Originally we tried to hire six trucks. Since the group left spontaneously, we had a very short time frame to organise this. In the end, we found four trucks to hire.

But one had an accident on the way to Tambura where we were meeting the group. We were left with three. We then hired an additional two trucks that were travelling with the group.

You also have to understand that people are very reluctant to hire out their trucks for use in this part of Sudan. This season is the worst time due to the rains, swamps and swollen rivers. Even now, I am worried about how we are going to get these trucks back to Uganda.

The other thing is that there is a shortage of trucks in Southern Sudan. While in Uganda, the trucks there often have maintenance problems. So we didn't have much choice.

It wouldn't have been easier to wait in some ways. If they left earlier, there would have been no water on the journey. If they left later, there would have been too much water due to the heavy rains and people would have got stuck. This period is the optimal moment to travel and then of course, they also wanted to be home for the establishment of an SPLM administration in the south

Do you have any other questions about the journey or want Bill to explain anything in his diary? Then drop him a line using the form below

The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.