It is very difficult to trace the path unless you wired it yourself and know the path.
I recently had to do the same thing in my Son's house. Part of a circuit went dead leaving one bedroom and the hallway light without power. He knew which breaker is was on, so that helped us somewhat. We pulled out all the light switches, light fixtures, and receptacles involved hoping to find a loose or broken wire. Nothing was to be found, but in pulling them we learned that most of the wires came down through the walls from the attic and back up there to go on to the next place.
By counting the wires in the boxes and the wires needed, it became obvious that there had to be a junction box in the attic somewhere to tie it all together, and we assumed at that point that the bad connection was up there. His attic has 18" of loose insulation blown in up there, so looking for it wasn't an option.
Instead of finding the impossible bad connection, we opted to parallel a new wire from the last good receptacle down through the floor into the basement and back up to the first dead one. We fixed it by bypassing the break because we couldn't get to the break to fix it right.
