Building help

Really I would just get an image of a Minecraft pumpkin then build off of it (use it like a reference)

What you consider 'very big' and whether you want the result to look realistinc or like the MC pumpkin are important constraints.

Try:
"minecraft pumpkin house"
"minecraft pumpkin build"
"giant minecraft pumpkin"
(all without the quotes) in your preferred search engine

You should get a range of sizes and style from wich to select…

Locally, https://www.planetminecraft.com/projects/tag/pumpkin/?share=schematic
gives these near the top;
https://www.planetminecraft.com/project/pumpkin-house-with-abandoned-village-and-many-jack-o-lanterns/
https://www.planetminecraft.com/project/halloween-pumpkin-5745688/
https://www.planetminecraft.com/project/pumpkin-patch-4127266/

[I've not looked at any of these beyong the title/splash pages.

Happy hunting]

I could make one