Is there any pack, mainly code, that would make it easier for me to just go and create most run of the mill zelda games, mainly talking about systems like enemies, menus, items, etc.? I mean, I could copy scripts from Solarus DX/XD, but I don't know which exactly I should copy, which to left in etc. I just want to start making the actual game, without reinventing the wheel.

[Christopho]

There is a lot of reusable code in the video tutorials, but no full pack yet.

How hard would it be to prepare one based on Solarus DX/XD codebase?

[Christopho]

Not very hard I think, but it will take time.
Note that code from Zelda Mystery of Solarus DX/XD is not always a great model because at the time they were done, the API did not have everything it has now. Not everything was as flexible as now. And most items are hardcoded in the engine (the engine was initially done for ZSDX).
Scripts from Zelda Return of the Hylian is cleaner, and they include full scripted items.

[Christopho]

There are currently two projects of Zelda packs:
- https://github.com/christopho/solarus-alttp-pack: Graphics and sound pack of Zelda A Link to the Past
- https://github.com/Nate-Devv/libsolarus-mudora: Zelda-like scripts (items, menus)
They are not complete yet, they need more work.
And maybe these two projects should be merged one day into only one.

[oclero]

And we could merge everything into a single Github organization: https://github.com/solarus-games