I had eight days allocated, so it was more based on me being a bit more gonzo. It didn't get dark, so I also enjoyed getting out and riding a long day. I packed too much food and took some back, so that wasn't as much reason. Since then I've mellowed some; for example cycling across gravel roads in Siberia a few years ago, I would be happy to stop at 55 miles with plenty of daylight left.

As far as the question about tires goes. For some of the muddy conditions, perhaps wider tires would have helped. For dry conditions, I've found a 700x35 is reasonable for myself and weight I've carried. I found that both on Dempster and also on Dalton and other gravel roads I've traveled.