I forget to change the lake radius often. After the dots are calculated, about 10 to 20 hours on my machine, I start kicking myself. I add a disk object now, then apply the water shader to it. This way I remember to get the lake sized correctly.
I like the composition of this. I don't like the fake stones (?) at the shore. They are probably based on a picture, but they do not look right to me. In heavily displaced cliffs and rock, I have found the calculations to get very long per subdivide cache box.