Rinse the pork roast under water to allow the rub to stick better.
In a mixing bowl, stir together brown sugar, onion powder, garlic powder, paprika, cayenne, black pepper, salt, thyme, and dill.
Spread the rub all over the outside of the rinsed roast. Gently place the rubbed pork roast in a large resealable freezer bag. Take out the excess air, seal, and freeze.
On the day of cooking, take the bag out of the freezer to thaw. Once thawed, place 1/2 cup of water and 3 Tbsp. of liquid smoke in the slow cooker.
Place the seasoned roast into the crock pot. Cook on low for 7-9 hours. Once cooked, drain the extra fat and water from the crock pot.
Use a set of tongs or two forks to pull the roast apart. After it's shredded, add 1/2 to the full bottle of BBQ sauce and mix through.