Preheat oven to 425 degrees.Combine brown sugar, salt, pepper, mustard powder, garlic powder, cayenne, and dried thyme in a small bowl. Pat pork dry with paper towels and rub all over with the spice mixture. Place on a baking sheet lined with parchment paper. Top with any remaining rub.In a large bowl, toss the potatoes and green beans together with the olive oil, salt, and pepper to coat. Place on a second parchment-lined baking sheet. Place baking sheets in the oven for 30 minutes, until potatoes are cooked through, green beans begin to brown, and the pork is cooked to 145 degrees. Remove vegetables from oven and turn on broiler. Broil 2-3 minutes to get a crust on the pork. Remove to a plate and rest for 5-10 minutes. Slice and serve with the vegetables.