In Dutch oven, heat 2 quarts (8 cups) water to boiling. Add linguine; cook 5 minutes.
Add broccoli and cauliflower; return to boiling. Cook 4 minutes. Add sugar snap peas and bell pepper; cook 2 minutes longer or until linguine is desired doneness and vegetables are crisp-tender.
Meanwhile, in small bowl, mix 1/2 cup of the Parmesan cheese, the sour cream, milk and salt until well blended; set aside.
Drain linguine and vegetables; place in large serving bowl. Add sour cream mixture; toss gently to mix. If desired, season to taste with pepper and additional salt. Sprinkle with remaining Parmesan cheese.