Alder

The Blender plugin allows you to import the .json models from your game's asset folder into Blender. You'll want to look up a tutorial on installing plugins, then import through the new import option it creates; File > Import > Vintage Story (.json)
At that point you can export them; File > Export > Stl (.stl)
The .stl format should be readable for whatever Splicer program you use for 3D printing. You'll probably need to resize the model in your splicer though

You seem to be pretty well-prepped!
I've heard from others you can continue to hunt during winter if you head far enough away, so if that is true, you can continue gaining meat should you run out of food.
You can also build a greenhouse using either quartz glass or crafting a bloomery from fire clay bricks to make clear glass. You also do not need a full ceiling of glass to build a greenhouse, I don't know the minimum, but I can confirm you can build at least a 5x5 greenhouse with 16 glass slabs, possibly less. That will allow you to continue farming into the winter, pay extra attention to the temperature requirements listed on the seed bags as a greenhouse only gives a buff of +5℃.
Other than that, I don't think I have any more advice to give on braving the winter, you seem to be pretty well prepared for the coming cold. Good luck!

Mark the location where you found the mushrooms on the map, they will eventually regrow within that area even if they've been entirely harvested.
That being said, I believe some mods allow you to properly cultivate mushrooms as well, but as for vanilla, there is no way to 'farm' mushrooms, other than returning to where they were found to see if they've regrown.