Yeah, I see that. For this one: strongly implied, logical, in use (the important bit), but not official.

Yes, move the junction if it is in the wrong place. The register is a good sign you found the right trail. source= (should be source:geometry) tells you I got this route from USFS data, which I download from their "clearinghouse". If you have a GPS track, it'll be a better source for the geometry. Move it how you like, please add access that I seem to have missed, please estimate trail_visibility (which does get rendered in places), just don't add a "TR" to the ref number because that's not proper.

I've not seen a lot of guidance for the exact location of a "trailhead", but generally it is on the trail while a register box would be, like a guide post, better mapped next to it.

I have mapped registers in the past as:
tourism=information
information=trail_register
since user defined values are valid.

Which trailhead? More important is to make sure an appropriate trail_visibility is set.

I have hiked this trail. This trail is used by peak baggers. The biggest problem with it is trying to decipher it from all the cow paths. Both ends are visible.

Even if it truly did not exist, mapping it and stating trail_visibility=no is information that communicates to the casual user that this will be a very hard route to travel whereas deleting it only makes it look forgotten.

I usually find it best, for an official trail like this, to map it as best I can and then set an appropriate trail_visibility.

Ah, same reason I changed Hardluck to Los Alamos over by Slide Mountain. The MVUM stuff I downloaded from the USFS GIS didn't have an opinion on that one, but it says this one is Sespe Road. If you slide down to the map on that page, you'll see the black line for the road is labeled "Sespe Road" (it is drawing from the same data set I downloaded). Underneath it is a white line labeled "Rose Valley Road" that continues on where the old Sespe River Road (until 1969? now trail) went.

So, the trailhead https://www.fs.usda.gov/recarea/lpnf/recarea/?recid=81832 says it is "at the end of the Sespe River Road, also known as Rose Valley Road." I see I called it Sespe River Road in a 2017 blog post and that was probably because Craig Carey called it that.

Consistency seems to be too much to ask.

Hi! I'm wondering why you reverted the name on Sespe Road to the old Rose Valley Road? I see that's what TIGER claims, but trust in that would be misplaced.