Such good questions and thinking. This is the part of the timeline that really confuses me, too. I am guessing that LE has much more clarity, and since they are protecting the friend's identity I am guessing they believe his story.
Here are my theories, all MOO:
1. Why was DK going to pick up the friend, instead of the friend just driving to the parking area at the bottom of Moose Creek Rd? I feel the answer to that question might provide clues. Maybe the friend didn't have transportation on Friday? Someone else had their car or their vehicle was not working. If that was the case, maybe the friend was able to find a vehicle that could make it up the rough rocky road by Sat morning to go look for him. Did the friend contact anyone else to ask about DK on Friday after DK didn't show up? That would back up his story.
2. It sounds like people knew where he was going, but maybe that was after the fact, we don't know. His sister talked about how he was going camping. Did she know where? Did the mother of his daughter know? I would guess the friend knew where they were going, and it would make sense that he would go look for him, because it is the wilderness and no way for DK to reach out if he needed help. This was a planned weekend "buddy" camping trip. The friend might wonder if DK's vehicle broke down, had flat tire that wasn't fixable, or he was injured/wild animal encounter, etc.
3. It may be that DK was going to pick the friend up because the friend's vehicle was not rough road worthy. Or the parking was so tight there, it just made sense for them to have one vehicle. If that was the case, why didn't the friend drive and leave his car in the parking lot at the base of Moose Creek Rd? Perhaps DK set up the campsite Thursday, and then Friday had errands to run in town, or work to do, and he was supposed to go into town Friday (If that is the case, and he didn't show up to whatever other things he was supposed to do, that would tighten the timeline of his death...).
What do you think happened?