If not in the will, or even additional to the will, there should be a clear specification of every bank account, stock portfolio, retirement/pension fund (including the govt ones, like military or veterans benefits), safe deposit box, storage locker, boat at the marina, cabin in the mountains, burial plot (including deeds in his possession of burial plots for ancestors and other relatives), insurance policies, and other important caches and documents (and keys). A list also of whatever in the house that he didn't own but leased or rented (e.g., my parents didn't own their clothes dryer ... it was leased from the gas company), so it's not sold or given away by mistake.
The will is frequently not read, or at least not read closely, until days after the death. So burial plans (including info on any prepaid funeral plans or burial plots), funeral plans, etc. should be a separate document ... readily available to the nearest family (presumably among the deceased's immediate possessions when he dies); this is a different situation than the will or financial data, as it is uncommon for funeral plans to be fudged by greedy relatives. Any directions for organ donations should be even more immediately available as the organs must be harvested (god how I hate that expression) immediately upon death. Also a list of people to be notified - this list should also be readily accessible, and should include full name, address, phone numbers, and maybe even a notation of how they are connected to the decedent (it might be a non-relative, even a total stranger, having to call family members and tell them about the death, funeral, or inheritance). I also recommend including the address and phone number in bequests in the will, to facilitate things even though those details might change over the years.
It's important to make sure that a number of trustworthy people, and not only relatives, but the lawyer, accountant, etc., know something ... at least where the will and the other documents are to be found. Unfortunately too many people either don't tell someone, or tell one person who turns out to be unavailable (or old/sick/senile) at the time of their death.
Although it might not be part of the legal work, it might be nice if a person contemplating his/her death wrote out or at least taped - while their handwriting was still legible and their minds still lucid - some family history, maybe some details about heirlooms and prized possessions, and some biographical data. Also mark up the photos in the photo album with all the info about who/when/where. When my mother died, I realized that I knew almost zero about her father, nor the birthdates/places of either of her parents or anything about their ancestors, nor whether there were any relatives on her father's side anywhere in the world; and, of course, it is now absolutely impossible to get those answers.
Good luck.