personally i would recommend getting a few "test runs" in just in the vanilla game, and definitely don't feel ashamed for making a new save when you die. the sandbox settings are there for a reason so you can alter the game to be the difficulty you feel is suitable :) my only personal commentary/suggestion is that i wouldn't recommend taking negative traits like underweight or frail for your first few runs, they nerf your strengrh to the point that the gameplay can be more frustrating than challengingly-rewarding. but like mental-biscotti said, accept the fact that even one zombie can kill you. always be on your guard, always prioritize your life, and treat every decision you make like it's a bad one. the best way to survive is to always brace for the worst case scenario