Awesome solo day hike. A long one but worth it! Took 4.5 hours from the parking lot to Mamquam Lake. Very few people from Elfin to Mamquam on the way there but many more on the return trip. Hiked up to Opal Cone on the way back and the views were amazing. Lots of glaciers in the distance. Alpine flowers abundant and the bugs weren't bad at all. Also, swimming at Elfin was popular with many other hikers.
Total hiking distance 47km, time: 10 hours 45 min including stops for water, snacks, pics and chatting with other hikers. Cumulative elevation gain was just over 2200m. Definitely a good workout and calorie burner!