We were at Lower Crystal Lake on July 27-28, 2022. This was our first overnight backpacking trip with our 9 and 12 year old. The Jeep trail felt a little challenging so we went up to the lake via Spruce Creek Road (Not Spruce Creek Trail) from the Trail Head then up via Wheeler Trail. It is debatable if that route was easier but it was definitely pretty. We went back via the Jeep trail.
There are a few established spots at the lake. The few that we found had rock rings that had been used for campfires. The one down the path along the lake has a very nice log that can be used for seating. That one was occupied and we stayed closer to the front of the lake on a hill. There were mosquitos! Taking insect repellent is a good idea.
The Jeep trail is used all night. We did notice cars coming in and out throughout the night heading up to the boulder field. In general they were quiet and not really noticeable but it can be a surprise seeing headlights at 2 am.