Fire up grill if using, keeping hot coals to one half of the grill or if using propane, only fire up one half of the grill.
Wash and cut all vegetables according to ingredients. Dry with paper towels.
Add olive oil, salt, pepper and garlic to large mixing bowl and whisk together. Add each vegetable category one at a time, thoroughly coating, leaving the mushrooms for last. Mushrooms act as sponges and will soak up the oil quickly if you coat them first. They require little oil, so coating them with remaining oil in bowl will be just fine. Remove onto a separate plate for grilling. Follow this procedure for each vegetable variety.
Grill each vegetable variety to your specific doneness. Check by tasting for doneness. Set aside and continue with each vegetable. Allow vegetables to cool to room temperature.
Arrange on platter, alternating colors for dramatic design effect. Add cheese and grilled bread if using. Sprinkle with lemon zest, fresh herbs and finish with lemon juice and/or balsamic if desired.