Frozen roast will take 2 to 3 days in a residential refrigerator to thaw. Cook until the internal temp in the center of the roast is between 135 and 140 degrees (carry over to 145). Roast between 300 and 325, it will take about 3 or 4 hours. Let it rest for 30 to 45 min, up to an hour
Cut all of the strings and make an incision about an inch in just under the skin. The skin should easily pull back and off (safe for stock or making green beans, or can be boiled then dried to fry for pork rinds).
Thinly slice and serve.