Yes, there is a use trail from LSL to USL, though we did not take it (we bushwhacked, not recommended), so you won't find it mentioned in my TR. A ranger tends to hang out at LSL, by the way. The use trail to Langley from USL is on the far right of the sandy wash as you are heading up.
The reason I ask about route finding is that there are a few places that can get confusing and topo helps. For example, if you take the use trail up the wash, at some point other use trails will split off. A topo map will show you that you want to curve left at some point as you gain altitude (following use trails), until you see Langley, at which point the choices are obvious. The use trail up the wash takes you nowhere near NAP if you do it right...it takes you directly to Langley (via a huge sandy plateau). Once you are done with Langley, you'll be on the huge sandy plateau, which you have to traverse to find NAP (southeast). Lots of use trails traverse the plateau, but a topo map will enable you to make good choices.....
