What is the ideal number of days to spend in Grand Canyon National Park (NP) in Arizona, considering the park’s vast size, diverse landscapes, and the variety of activities available? Could you provide a comprehensive guide to planning an itinerary for 1 day, 2 days, or more, taking into account the best ways to explore key attractions, hiking trails, scenic viewpoints, and nearby areas like the South Rim, North Rim, and Inner Canyon? Additionally, what are the benefits of spending extra time at the park, and how do the different seasons, weather conditions, and personal interests (such as hiking, stargazing, or photography) impact the ideal length of stay?