Kilimanjaro is a wonderful climb. We did it about nine years ago and didn't do any specific training. Just our regular hiking in the Whites stuff. Most of our days were about 6 to 8 miles in length. At higher elevations on Kili the trail became steeper and with scree, so I would suggest trails that have scree so they know what that feels like. I remember my legs feeling really tired as we were coming down in the area below Gilman's Point for a few hours. The guides tried to get us to ski/slide down through it. We tend to concentrate our efforts in going up the mountain, but half the trip in footsteps is coming down the mountain, so include declines in training. In my estimation, a very important training will be for altitude, which you can't train for here physically. But you can train mentally by realizing what to expect will make a difference. Over 10,000 feet and they will begin to feel effects they are not accustomed to. Of course there is the potential for HACE and HAPE, which I hope they are able to avoid, but everyone has HAFE (high altitude flatulence expulsion) or gas and bloating. Unexplained feelings and sensations cause fear, i.e. if you don't know that how you are feeling is related to altitutde and somewhat normal, you might think you are ill. Also, food doesn't taste good (not the fault of the cooks or the quality of the food they bring, it's the altitude). We took the longest trip we could and found that gave us more time to become adjusted. We hiked slowly. The guides insisted on that. Water - drink, drink, drink. We didn't take drugs for altitude but asprin and tums made a differnece. Also, candy to change the taste in your mouth. Food was unappealing up high. There was nothing in the world I would have chosen to eat, but eat you must.