Green River Lake is a beautiful lake ... and you're lucky to live so close (it's a 2hr drive for me ...LOL!)
The Crappie are generally pretty cyclic on GRL ... couple of years of small fish, then "BAM" - Slabs out the wazoo :D
I haven't fished GRL in a few years ... but, the areas I've done the best in are around the island (on the marina side) - the "beach" area of the campground - the "flats" off the end of the campground.
Mostly I've trolled a 1/32-1/16oz Chartreuse Roadrunner on the beach & flats ... and cast it (or tube jigs) to the bank cover on the other (marina) side of the island.
I believe the "marina" is called Emerald Isle Marina - and the "campground" is the GRL State Park (Lone Valley Ramp). The "island" doesn't have a listed name ... but the "cut thru" is straight across from the State Park.
Get yourself a Fishing HotSpots map of the lake - it will be a big help to you, in finding these spots (and those you'll find on your own). ....luck2ya ...cp