Getting all loot packages: there's a way to re-access out of map locations?

[Metalloman1]

Not that I have much hope but I need to know if I can re-access the castle entrance location, where all undeads are, just to try and take the package in there.

There's a way at all or I need to restart the story mode?

Thanks in advance.

[Obey138]

After you open Story mode menu, there's an option to restart a selected mission, next to load last save file.

[Metalloman1]

Oh! And restarting a mission allows me to pick up the eventually left package?
I thought that it was some sort of mission-specific trial mode, unbonded from everything else.
Well, thank you! :D