The trip up to Clara and Marion lakes was a quiet and beautiful one! There were three other cars at the trailhead but I did not run into anyone on the trail. There were a few bugs, particularly around the lakes and other standing water near the trail, but they were not too bad yet. The trail is in good condition, slightly rocky in some sections and a few fall downs but overall good. As said by others, the majority of the elevation gain comes early on in on the trail. It took about two hours roundtrip including a lunch break for a nice short solo hike.
Take note that there have been reports of people breaking into vehicles parked along squilchuck road, so be sure to be cautious when leaving valuables behind.