For the best campgrounds near McKinney, TX, such as Collin Park, Hidden Acres, and Erwin Park, it's smart to book 4 to 6 weeks ahead for weekends, especially in spring and fall. Most take online reservations through their website or the city portal. For last-minute trips, weekdays often have available sites, even at busy parks. Book early, and you'll snag the best lakefront or shaded spots.