Hiked up to Greendrop this past weekend. Took us about 7 hrs round trip and we are not terribly fast hikers. The trail up to Lindeman is a nice "grind-type" hike and is pretty busy. Lindeman Lake is absolutely beautiful.
The trail from Lindeman to Greendrop took us approx 3+ hrs return and goes through several rock-slides. It was less busy than the trail to Lindeman. Definitely not as vertical as the first bit up to Lindeman. Be careful to watch for trail markers - especially on the way to Greendrop -- as its easy to veer off onto what looks like the correct trail but isn't. Greendrop is pretty, but a little anticlimactic after seeing Lindeman. Both lakes have wooden tent platforms, outhouses and bear proof food storage for overnight tenting.
If you are going all the way to Greendrop shoes with good grips are recommended for crossing the rock-slides "bouldering".