The DVD does not have much advice for those doing it 'solo', without a trekking company. It's difficult for several reasons, but here are a few tips:

• You need a Trail Permit - unless you get a permit through a tour company, you will need to visit the Kokoda Trail (Track?) Authority Office in the Brian Bell Plaza in Boroko to get your permit. I think you would have to do this in person. There are supposed to be offices in Kokoda and Sogeri, but I haven't seen them. The regulations are that to get a trekking permit, you have to name your guide (who must come from one of the Trail Villages). Permits are not policed on the Trail.
• You need to get a guide, and if you want a cheap local Koiari guide at the Moresby end, you can visit their 'area' - at Six Mile, along the Hiratano Highway, just before the Six Mile Dump. But it's really rough area, and I'd recommend you stay away. Another way would be to just ask around your hotel in Moresby - someone will know someone and one will turn up sooner or later. But it's time consuming in a rather uninteresting and expensive Moresby.
• You could likely pick up a guide much easier at the Kokoda end, because Kokoda is a reasonably sized village and has young lads with not a lot to do. But then you have to have your permit. Also, you will have to supply backpack and food for yourself and guide - do the math and it will weigh a lot - you would also be well advised to buy some sort of warm jacket for your guide - he will possibly just have the shorts he stands in. There is some food in villages along the way - but this is pot luck - they don't always have excess. Porters will claim to have several aunties in every village , but they are sometimes 'away' or just don't have food to spare. There is no village at the Owers Corner end - just a few houses, so not many potential guides there.
• Most young men are very helpful and hardworking, but you may get a 'dud'. He may be on the run from the police (I've had one), or be unwelcome in a village along the way, or will make excessive demands for extra pay or extra whatever, either during the walk or at the end. And you will probably get someone without much experience at a measured walking pace, who you will struggle to stay with. PNG folk are generally not used to the much slower pace of expatriate trekkers - they just go hard all day long.
• There are very limited regular flights to Kokoda, more to Popondetta, but then you will have to get a bus ('PMV') up to Kokoda. You could get stranded at the airport in Moresby (you haven't lived till you have been 'bumped' - offloaded - several times), or find it hard to get a PMV from Gurney Airport (yeah - the name seemed funny to me as well) to Popondetta town, or miss a PMV from Popondetta to Kokoda, which will take about 3 hours. So you see, there are several problematic connections on this route. Coming the other way, you will have to get from Kokoda to Pop, which would be easier. You would overnight in one of several cheap guesthouses in Kokoda Then grab an early PMV to Pop (and get a seat- luxury!) and get an afternoon flight out .. if you are lucky. Unfortunately Tour Companies often near fill planes out of Pop, so you may not get a seat.