Walnut, California is a great city to explore on foot. If you're planning to explore Walnut, consider renting a car for better flexibility. Renting a car would cost you around $50-70 per day. Alternatively, you can use ride-sharing apps for a more affordable transportation option.
If you only have one day in Walnut, it is best suggested to visit the Walnut Ranch Park, Walnut Historical Museum, and the Mt. San Antonio College Wildlife Sanctuary - the most popular spots in the city. If you have an additional day, add a tour of the Suzanne Park, and Pleasant Valley Marketplace.