A few things to consider from someone who has done it.
1. You can not see if any caribou are present at the location you decide to make your 5 mile march.
2. Some areas are better than others for the march.
3. Have the best spotting scope you can afford.
4. If something goes wrong it is a long way back to the truck.
May people don't understand caribou much like myself. Some get lucky and some learn. There are a lot of caribou, but there is vast amount of area they can be. You can pick an area and not have a caribou with in a hundred miles you. If you see them close to the road. It does not mean they will be present after the five mile mark. I watched a couple nice bulls all day from the 5 mile mark. They were 4.75 miles out and never moved over a couple hundred yards all day. I think this why so many bow hunt. you can cover so much more area and spend time hunting where you find caribou. All that being said I enjoyed my hunt and would do it again. If you really want to kill a caribou and not just the experience. I think a transporter is the way to go.