Special equipment: A meat thermometer
Prepare a grill for medium-high heat, leaving 1 burner off (for indirect heat to finish the tenderloin). Line part of the direct-heat side with foil. Combine the granulated garlic, mustard and 3 teaspoons salt in a small bowl, and rub all over the tenderloin. Generously oil the uncovered grill grates, and grill the tenderloin over direct heat (not on the foil), turning occasionally, until well marked, about 12 minutes. Move the tenderloin to the indirect heat, cover with the lid and cook, turning occasionally, until a thermometer inserted in the thickest part registers 145 degrees F, about 14 minutes more. Transfer to a cutting board, let rest a few minutes, then cut into 1/2-inch chunks. Meanwhile, toss the broccoli and tomatoes with the oil, 1 teaspoon salt and a few grinds of pepper. Grill on the foil, turning occasionally, until the tomatoes are charred and starting to burst, 6 to 10 minutes, and the broccoli is charred and tender, 10 to 15 minutes. Transfer to a large bowl. Cut the tomatoes in half. Bring the half-and-half and macaroni to a boil in a large pot over medium heat, stirring frequently. Continue to cook, stirring, until the macaroni is tender and the half-and-half has thickened to the consistency of heavy cream, about 5 minutes. Remove the pot from the heat, and stir in the Cheddar, butter and 1 tablespoon salt. Stir until smooth, thick and creamy. Add the grilled pork and vegetables, stirring to incorporate. The mixture will thicken as it sits; adjust the consistency as needed with hot water before serving.