I have not the time to mod anymore (because IRL and also i don't remember :-) ) so I propose my work for those who want. Feel free to do what you want with this, just credit to me.

I have combined Solitude Docks, Solitude Expansion, Radioactive Solitude docks and Solitude Exterior Add-on.
I changed the road that leads to the docks and I created a staircase that allows access to the new neighborhood added by Radoactive solitude (the original mod obliged the player to make a great detour : thoughtful: ).
I also made pacths for Lanterns II, Laundry, Better Roads and Realistic Water 2 (which can be used with Landscape Grass Fix too).
The mod is not complete. I have a problem with lods: On the first picture, I added a mill. And the moulin blades disappear after using Dyndolold. I also think there problem owith Navmesh. In Creationkit, I can not bind some triangle with new triangle.
No crashes encountered, nevertheless FPS falls, perhaps due to the Navmeshes precisely.
I must also combine the mod with Solitude exterior add-on and would need advice to clean, and to track the bugs / glitchs.

The rendering is frankly not bad.

PS: I think I've made a lot of mistakes with masters and files dependencies, sorry.

Mode required
-Solitude Expansion-Solitude Docks
-Radioactive Solitude Docks-Solitude exterior add-on