Is listing that person in a will enough or are other documents necessary to ensure a trouble free transfer of home title?
Using a will does not give a "trouble-free" transfer. It guarantees a probate court procedure on your death. There are other ways, like deeding the property in joint names, executing a Transfer on Death (TOD) deed, executing a life estate deed, or creating a trust. Each solution has its specific advantages and disadvantages. The most flexible is creation of a trust. The least flexible (arguably) are joint tenancy or life estate, since they cannot be changed without the other party agreeing. But those ways have their advantages also, including protection from Medicaid liens.