Temperature and stuff are already in the base settings. But I can highly recommend a lot of the "Fauna of the stone age" mods, and there are a few mods that add natural plants and things, most notably the floral zone mods. You might also want to look into long term food storage and primitive survival mods. Arctic tweaks is probably a must have, depending on how low you set your temperature..
Here's a few links, you can always look around yourself :)
https://mods.vintagestory.at/arcticsurvival
https://mods.vintagestory.at/terraprety
https://mods.vintagestory.at/floralzonescosmopolitanregion
https://mods.vintagestory.at/list/mod?sortby=downloads&sortdir=d&text=Fauna+of+the+Stone+Age&side=&a=&mv=&c=&t=
