Wait for it to probe tender*, let it cool until the internal drops 8°, then wrap and hold in an insulated cooler using wadded up newspaper or some towels for insulation. Check it after 3 or 4 hours just in case you need to move it back into the oven to raise the internal temp. Ideally you want it to be above 150° while in the cooler.
*probing is more accurate than the internal temp. Room temperature peanut butter is the feel you are looking for.