I have a National Geographic map (Yosemite Southeast) showing a trail labeled 'Post Creek Trail' connecting the Fernandez Trailhead with the Post Pass Trail. But the USGS map and the NPS Yosemite map don't show the trail at all. Anybody know if the trail exists and, if so, what condition it is in? If noticed some discrepancies on the Yosemite Southeast map previously, so its credibility is suspect.

I tried to use this trail back in 2009 on a trip to Mt. Ansel Adams. From my notes:

"The Mytopo map of the area shows a shortcut trail to Post Peak Pass that I attempted to follow. I found the junction just past the Fernandez Trail junction, signed for Joe Crane Lake. I took this thinly-used trail a short distance to another sign that indicated the trail I wanted, signed for Post Creek. This trail appears to have been abandoned some years ago and was very hard to follow. Downed logs and overgrowth conspired with the inky darkness to make this a very slow route and I abandoned it within about five minutes. There was no telling how long it might take and I figured it would be better to do a few extra miles on a well-used trail instead."

I was trying it at night, so it might be easier to follow during the day, but I would think the downfall alone might make it more pain than it's worth.

I would only add to Bob's sage advice. I visited the area in 2011, the last really heavy snow year, after a 46 year absence. I followed the Post Creek Trail without incident from Isberg Pass to the Rutherford Lake / Fernandez Pass 4–way junction (seen at approx.1:39 in my pre GoPro video of the trip https://www.youtube.com/watch?v=x_BlYWIdX_k), where the trail clearly continued downhill a couple of miles to the the "California Riding & Hiking Trail" (?) and other intersections leading to the Fernandez Pass Trailhead. The NGS map was recommended to me as being "most" accurate by Rangers when I got my permit. I found it generally concurred better with my faded, corner worn 1950's USGS quadrangle than any of the newer maps. They also advised that only a few of the lower Clover/Soldier Mdw. trails and Isberg had been cleared of massive downfall at that late date.

That said, the area has a lot of confusing intersections and trails, made all the more so by dense forest below 9,500 feet or so. My Yosemite Trail rule applies here as well as any. Any trail either not used commercially by pack stock, or within a mile or two of habitation is likely to be in poor repair and/or suspect.

I dug out my Sierra National Forest Map (circa 1991) over the weekend and saw that the 'Post Creek Trail' was shown essentially as appearing on the Yosemite SE map. However, some trails on the NFS map were shown in bolder type than others (the Post Creek Trail was not bold), but the map legend did not explain the difference. Ironically, the National Geographic map has the same problem: some trails are printed in red and some in black, but the legend only shows red.