Just to clarify ... Green River "Lake" is where the marina/floating cabins are.
If you go above the 551 bridge, where Casey Creek & the Green River merge, then yes it is a shallow river ... with lots of sand bars & stumps. Just do a Google Maps search and turn on the satellite view & zoom in on the SE section of the lake, and you'll see what I mean.
Otherwise, the lake itself is wide/deep, with few areas with hazards to be on the lookout for. That Google Map satellite view is currently showing a "winter time" view, when the water level is down, so a lot of the banks are exposed & shallow banks that stick out into the lake are easily noticed.
Were I fishing at that time of year, and from that part of the lake (dam area), I'd be fishing around the island, and back into Robinson Creek ... starting at the State Campground and going up into Robinson Creek as far as Smith Ridge or Pikes Ridge campgrounds.
You can check out this site to give you the areas (& GPS coords) where the KDFWR has placed fish attractors : https://www.google.com/maps/d/viewer...546499999&z=13
According to the COE Lake Level chart ... mid March is when they start letting the lake start filling to Summer Pool (by mid May). So the lake will still be low, unless heavy rains occur. You can track the lake levels on this site : Louisville District Daily Lake Report .... and if you click on the blue highlighted numbers of Green River Lake, under the Today's Pool Feet column, you get a chart showing the past year's lake level rise/fall, precipitation amounts for the area, and the inflow/outflow data.
You can also get a daily level/temp report by calling 270-465-8824 ... but, take into consideration that water temps are likely taken at the dam, so they could be higher or lower in other areas of the lake.
As to how to fish the lake ... all options are open. That time of year, with the lake level being down (if it is) ... I'd probably fish around the attractors, and if they fail to produce I'd opt for longline trolling.
Now ... if you intend to fish "upriver" from your floating cabins, like up around the Holmes Bend area and on up towards the 551 bridge ... I'll defer to the other members that fish that area regularly.