@trust812
As for the trust, it has obviously been in existence a long time and there is nothing you need to do to get permission to handle its affairs. As for the personal estate, I will defer to @Anonymous_ , except to add that #1) you may want to double check with state law (for example, if the personal estate is over a certain dollar amount, you may still need the court's approval for other reasons even if the IRS doesn't require it) and #2) if there is a dispute in the family about who should handle your father's personal affairs, you may still need to go to court. I would guess, based on the long term existence of the trust, that this has already been worked out, and the personal estate may be very small if most of your father's assets are in the trust. But I mention it just in case, and for anyone else who may be reading this.
