In a large bowl, combine the first 6 ingredients and stir well.
Add the squash, zucchini, bell peppers, and mushrooms to the bowl.
Toss well to coat the vegetables.
Cover and marinate in the refrigerator for 2 hours, tossing occasionally.
Drain the marinated vegetables and thread them alternately on skewers.
Grill the skewers, covered with the grill lid, over medium heat (300° to 350°) for about 12 minutes or until the vegetables are tender, turning them once.
Enjoy your Grilled Vegetable Skewers!
Notes / Tips / Wine Advice:
Note: If you’re using a grill basket, grill the vegetables in 2 batches in a single layer.