ok, I'll have to be the first to admit I must be missing something in this discussion. the subject trail exists. I've been on it a number of times, finished it once- and at that time I didn't carry a gps, so a track log of the trail was not created. no position fixes, either. it does not appear on any topo map. how does one mark a route onto a topo, under those circumstances?
Okay, I'm going to offer a more detailed answer that focuses on that question, but the short answer is you do that from memory.
Here are some details...
In practice you need to be able to read a topo map and recall the route you took and then draw it on the map. You'll just have to estimate the route and elevations as best you can.
The real trick to doing that with any degree of accuracy is paying close attention to the main ridges, the main hollows between them, and all the smaller cuts along them that lead from the main hollows to the main ridges while you're hiking through them.
You need to be aware those features on each side of the ridges or valleys as you travel no matter if you're mainly on a ridge or in a valley, or anywhere on the side of a mountain. You have to count them as you go. Some of them may even have names, and those that don't you can name for your own use if you want.
Generally speaking this is called "reading the lay of the land". I don't mean that to be a wisecrack, I say it to differentiate between formal navigation and the less formal getting around without getting lost.
For example, if the trail heads along the bottom of a main valley there will be a main ridge on each side of it. As you head up the main valley there will be smaller valleys, or "cuts" in the main ridges that shed water into the main valley. A trail heading to the top of a mountain from a valley will generally, at some point, leave the main valley and start up towards a ridge on one or the other side of the valley. If you count the number of cuts before it heads up and compare that with your topo maps and you'll be able to locate yourself pretty accurately. Keep doing that as you climb, and estimate how far up or down you've went, and you'll still be able to locate yourself on a map.
I looked at the topo maps and satellite photos for where you're going and those are some big land features your hiking. There are big ridges and big valleys and big cuts. You'll almost always know exactly where you are on a topo map if you've paid close attention to the lay of the land there.
If I were you, just for grins, I'd print a map now and draw the trail on it where I think it is, then when you hike the trail again record your track with a GPS, or draw it on the map again, and compare the two routes. If you really put your mind to it you might do better than you may think. And even if you know that you really don't have a clue where to draw the trail it should be fun to take a crack at guessing.
I hope this helps.