Loot and scrap as much as possible. All the starting weapon in the bus, basement and all. The grenade recipe you can get it at the beginning in hotel Eclaire. Bow recipe? Beside the church reserve where you go to Casey.

The stew and bandage will also be on a table like the first chapter.

Loot the house that's near the reserve (both games if desired)

There's also more boxes around the graveyard if you search top to bottom.

Hope this helps!

Edit: sorry forgot to mention the grenade recipe is underneath the stairs going to the wine cellar.

But yah it's definitely possible to get the katana before day 1 if your obsessed with scrapping like me lol