John, all bank accounts, 401K or other investments, and life insurance policies have named beneficiaries (and usually first, second and even third choices), so none of that passes through a probate estate (if any), and need not be mentioned in a will.
What you want is no probate estate at all, if possible.
What you have left is personalty (stuff) and that should easily be disposed of by a will. In as much or little detail as you want. And, if you already have a will, you can add a handwritten list of what to whom, who you must trust your 1st named executor to carry out in accord with your wishes. It's also not a bad idea to give things to whom you want now, if you don't need them now.
absolutly always have a beneficiaries or joint accounts an you finances.
Trusts (inter vivos pour-over) are for people with larger estates who want to control how money and assets are distributed over time after their death (sometimes for many years). (So someone doesn't blow it on liquor, blow and whores in 3 months.) Plus trusts can be pretty expensive to set up, and then often need upgrades and corrections because of changes in law and taxes as time passes, also for a price for each revision.
Just make sure you have a valid will in your state (and tell your first choice executor where it is and how to get it). And you can often go on line for simple will instructions (and rules) for your state.
