Only the basics out in the field (alchemy, crafting, smithing):
* Alchemy: You only carry mortar and pestle, the rest of the equipment is either too fragile or too heavy (lookup real life calcinator).
* Crafting: Make arrowtips from stone and arrows from shaped stone and wood. No advanced diamond cutting in the field
* Smithing: Basic repairs of weapons, like keeping a blade sharp. Broken weapons or advanced repairs to be done at the shop.
And nothing too painful at normal difficulties. I'd prefer different difficulties for different aspects of the game.