A nice easy hike for any day, really. The views of the lake are great all along the trail. I started at the "main" trailhead off East Beach Road - it was 11AM on a gorgeous Sunday and the lot was full, so I parked up the road a bit.
The trail itself is pretty well maintained, and once you get past the punchbowl it wasn't terribly crowded. I will say I was a bit disappointed with the bridge and punchbowl, but that might be because of how many people were there - it was difficult to even get over the bridge, as you had to wind your way through the crowd. There's a nicer view of the lake at the 2 mile mark, with a couple nice rocks for sitting in contemplation.
The "tunnel"/ cave is a little more than a mile east of the western trailhead (see map below), though you're not going to see it on your way west unless you happen to turn back at the right moment. The trail does not go through it - look for the area where the trail has been relocated away from the lake due to a rock slide, then turn around. Or watch for it on your way back east.
Judging by the groups I was walking back through in the later afternoon (and what said groups were doing), it seems like this trail might be a popular place for teens to come on nice days to drink, smoke and party, so an early start is probably better.