You could start with mods that change the environment. This will greatly change the way your game looks.
Here are a few mods that I recommend:
Vivid Fallout - All in One
Dustbowl Overhaul
Winter Overhaul
True Grass
You could then search Gun or Nexus and try out the gun mods and see which one you like/which weapons you would like to replace their vanilla counterparts.
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Will there be enough Dakka?