Final answer:
The most essential part of a hunting plan to leave with someone is a detailed itinerary, along with a map and emergency contacts. These ensure your safety by providing clear information about your whereabouts and plans for emergencies.
Step-by-step explanation:
An essential part of a hunting plan that you should leave with a family member or friend is a detailed itinerary. This includes information such as your expected locations at certain times, when you plan to return, and what to do in case you do not return as scheduled. Along with the detailed itinerary, it is also wise to leave a map of the hunting area and a list of emergency contacts. While not something to leave behind but rather to carry with you, a first aid kit is crucial for handling any potential injuries that could occur during the hunt.