Place the bacon in a large skillet set over medium heat. Cook until golden brown and crisp, turning occasionally. Transfer to a paper towel to drain.
Break the spaghetti noodles in half and cook according to package directions. Drain and rinse with cold water.
In a large bowl, combine the red bell pepper, zucchini and onion. Gently toss with the olive oil, rosemary and salt.
Heat an outdoor grill or grill pan to medium-high heat. Cook the vegetables until lightly charred and tender, about 2 minutes per side for the zucchini and 2 to 3 minutes per side for the red bell pepper and onion. Transfer to a plate and cool to room temperature. Cut into bite-sized pieces, discarding the root end of the onion.
In a large serving bowl, combine the spring lettuce mix, cooked spaghetti noodles, roasted vegetables, basil and bacon. Toss with the dressing. Serve.
In a small bowl, whisk together the white wine vinegar, Dijon mustard, maple syrup, salt and pepper.