After visiting the First Borough for sunrise a few years ago, Dad (https://steveinjapan.aminus3.com) and I planned to visit Mt. Fremont as the trail to the lookout intersects the route we were on, and it looked promising. Unfortunately, he never made it to Mt. Fremont as far as I know, although he might've been up to the lookout in his younger days. The trail features stunning vistas and a fire lookout. When I was there, a ranger was at the lookout. While no longer active, the lookout is listed in the National Register of Historic Places.
Anyway, I think he would have enjoyed the view of Mount Rainier from there.