I had similar issues both days. On day 2, I kept losing the trail going east to west, and I'm lucky it didn't cost me more time. I did better on the way back because I realized I normally mainly follow a trail by looking down at the path, but for this trail, the best strategy was just to keep looking up, spotting and following the orange blazes. As to day 1 stone walls, I had the same problem never seeing them on the map until I hit them (but then I could find them!). I think it's because my mind is trained to ignore straight black lines because they are usually N-S lines, and so they are sometimes invisible to me when I'm planning and following my route.