Preheat oven to 450 degrees.

In a large bowl, combine squash, red peppers, sweet potato and Yukon Gold potatoes.

Separate the red onion quarters into pieces and add to mixture.

In a small bowl, stir together thyme, rosemary, olive oil, vinegar, salt and pepper.

Toss with vegetables until coated.

Spread evenly in a large roasting pan sprayed with non-stick coating.

Roast for approximately 40 minutes, stirring every 10 minutes, until vegetables are cooked through and browned.