These textures have some soft dependencies, since they are designed to blend well with particular textures. I would recommend installing SMIM (has special dirtcliff meshes which this mod retextures), then Skyrim 2020 (2.7 then overwrite with 2.8) by Pfuscher, then LH's dirt cliffs from LHmods.com (you'll overwrite most of it), then Septentrional Landscapes by winedave. You want all of LH's dirt cliffs, the main mod, the SMIM addon, and the dragonborn addon. Basically the goal is to use Septentrional's cave ground and snow textures, Skyrim 2020's cave walls, LH's dirt cliff roots, and have them all blend together correctly, which is not a trivial thing but this mod basically achieves that, assuming you use that combination of mods, or textures with similar colors. Really as long as your cave walls have some amount of moss on them, and you don't overwrite the cavebaseground02 textures included in this mod, it should be a significant improvement over the vanilla textures or any other retexture which uses the vanilla alpha channel (all the ones I've seen do, I guess they just forgot about the alpha).

The vanilla alphas look pretty goofy and blocky so they couldn't blend well regardless of what kind of texture you put in the RGB channels. True for all types of dirt cliffs and cave surface edges really. You couldn't fix it with a smooth gradient either since all the meshes use alpha testing and no blending. So to make an alpha for a mask or some other texture intended to blend with others, and have it work well with testing, you can just dissolve the gradients into little solid particles. Like how comic books were printed back when a dot of ink could only have two strengths: 0% or 100%. Bethesda kinda did this on the upper surface of the cave roots but didn't do it on the lower surface so you get this really weird collar on the corner of every cliff. So I massively increased the number of 'particles'.

There are other problems with cave textures though, like ice caves have ice or snow on almost every surface but the ground textures are usually just rock. Of course it doesn't make sense for there to be snow inside a cave, but if the walls look all icy then we can't blend them with the ground unless the ground also looks icy or snowy. So I have changed the ice cave textures too. They should look good with Septentrional Landscapes (I also recommend downloading Hyperborean Snow since my snow textures are meant to blend with those) and I recommend downloading all of winedave's textures since they're just really good and they have such superior alpha channels to most other retextures.

The alphas are really a big part of making the landscape surfaces realistic, since no matter how good your photogrammetric textures are, it is so jarring when you run into a texture seam between 2 materials or even just a blending pattern that doesn't make sense for what you're seeing. Like say the grass has flowers and ivy and ferns ostensibly sticking up from it. Then the alpha which blends it into another texture should have the flowers, ivy, and ferns visible while the grass starts to disappear. But instead you often see just a generic dissolving applied to the whole thing, so you just see little flower particles everywhere as if someone ran a lawnmower over Skyrim's fields. Pfuscher's textures are also really good in that respect so that's why I based this mod on blending those textures together.

SMIM adds some cave meshes with their own texture paths. One is like a mossy version of cave roots and the other is the same thing but with snow on it. LH's mod is the only one I've seen that doesn't miss those. But the alphas cut off the little roots, and are too blurry with the big roots, causing black edges on everything since the alpha test threshold is so forgiving. So I made the alphas actually make sense for the new roots, then blended them way better and contracted the roots a bit to reduce the dark edges, which cause a cartoonish, borderlands-esque effect otherwise.

I also made a new dirt cliff mask to help blend LH's dirt cliff textures. This helps ensure his textures will blend well with any landscape textures you might use. The ones that might be less likely to blend well if you don't use the mods I suggested are the cave cliffs. The ice caves will blend fine if you use my ice cave ground texture, but the green caves might look pretty weird if you have cave walls with no moss, or cave dirt that's way brighter than the one in Septentrional Landscapes. Specifically talking about cavebaseground01.dds there. So you CAN just grab individual textures from those mods, just don't forget the normal maps. cavebasewall01-05 are the corresponding walls.