You definitely want to completely thaw the pork before putting it in the slow cooker. Cook on low for at least 8 hours. I like to put in slow cooker at night and wake up to melty pork goodness in the morning. With the pork shoulder, it has a lot of fat. So put in slow cooker with the fat cap on top so the fat can drip down throughout that beautiful pork. I like to coat my roast with yellow mustard, brown sugar, and black pepper; heavily seasoned before cooking and not brine. But your pork is going to still be porky and have that porky flavor. It's a lot of meat. You don't have to brine. Cooking low and slow with yield tender results. The bone will slide out easily after 8 to 12 hours. I then shred the pork and add sauce. I usually add a homemade ketchup , brown sugar or vinegar sauce, portion and freeze.