Hangman's Alley is one of my favorite settlement locations due to its central location and proximity to Diamond City.  However, as an avid user of Build High - Expanded Settlements I found there were some issues with the landscape in the area, primarily in the waterfront.  Essentially, in an effort to make the area look more trashy, Bethesda lifted the terrain over the road at parts, leaving an unscrappable mess in the area.  Even worse, if you use a scrap mod like Scrap Everything and try scrapping anything on the main road leading to Diamond City, their are quite a few gaps and holes in the terrain that look terrible.  Hangman's alley also has copious amounts of terrain with trash textures, which give the area an especially run-down look no matter what you build in it.  This mod fixes these problems to the best of my ability by lowering/leveling the terrain, patching the holes in the area, and repainting it to better more evenly match the surroundings.

The entire area of the main settlement was re-leveled, and is slightly lower then it previously was.  I tried to make it line up as best I could, but the CK's terrain tools are somewhat sloppy (and I"m fairly new to it).  Overall however, you should find it a lot nicer then it was previously.  I had to add a hill against the far right side of the settlement to prevent a massive gap that arises, but everything else is leveled off. I also fixed several gaps outside in the main road, and lowered the terrain on the waterfront roads outside

I've tested the area with NPCs and they have no problem walking on and using the area.  I've also tested with Hangman's Alley Interior Apartments and NPCs are able to enter the apartments with my changes as well.  If you do use HAIA, make sure you load it BEFORE my mod, so my landscape changes take precedence. There may still be some issues or changes with the landscape or navmesh that I wasn't able to find, so let me know if you find any dead zones or hovering objects. If you'd like a mod that does more to actually clean the settlement of trash while also fixing things, also try maddogfargo's MDF Hangman's Alley Clean which I didn't know existed until I created this mod! It should theoretically be possible to load the both of our fixes together, just try loading his AFTER mine.

Technically there are no requirements to use this mod, however it is designed for use with Build High - Expanded Settlements.  You can install it without using Build High or even using a different settlement expansion mod and it should still work, however.  

Installation
Use a mod manager like Mod Organizer 2 or Vortex to download, and install from there. Alternatively, manually download the file and place it in your Fallout 4/Data directory, then enable it using your mod manager of choice.  The file is an ESL marked ESP file, so it shouldn't count against your load order. The file has also been manually cleaned using FO4Edit

Known Issues
- The planters directly on the main road outside Hangman's Alley that are normally filled with trash still hold a portal to the void if you scrap them. I tried to fill them up but there was no way to do it without clipping through the walls
- Some of the area may seem a bit lumpy.  I tried to even it out the best I can but the leveling tools don't seem to work in my favor all the time. If there's anywhere that's especially egregious, let me know.
- This mod does break precombineds in the area as I'm not exactly sure how to recompile them, and Build High and Scrap Everything break them anyway.  If this becomes a serious request I'll try and figure it out, but I personally make sure none of my settlement areas use them.

Recommend Mods
Build High - Expanded Settlements
Scrap Everything
Hangman's Alley Interior Apartments
Homemaker - Expanded Settlements - Shameless plug

Credits
ElminsterAU and the xEdit Team for FO4Edit
Themon for Build High
shadowslasher410 and VIitS for Scrap Everything
Purple Radiation for Hangman's Alley Interior Apartments
Bethesda, for Fallout 4 and the Creation Kit