Mount Fremont is one of Mount Rainier National Park's four surviving fire lookouts, and the most easily accessible and most visited. It's 5.6 relatively easy miles round trip from Sunrise, and commands spectacular views of Mount Rainier and Grand Park. Because it's so popular, it's essential to plan this trip early on a weekday, or to arrange an overnight expedition. More details at
https://visitrainier.com/mount-fremont-lookout-2/.