For the beach, I have ideas. But only on the sand , and near the sea ! If you place surrounding forests or other things "not-beach" , what I wrote don't help you.
Floors :
DCZFLR10 (Sand clear yellow), DEM1_5 (Same, but darker, more brown.)
On the other hand, I advise you to avoid QUIKNOAN. It contain a zigzag sandy brown and yellow.
Personally, I prefer the sand of one color.
In the game I made, I used this tip to decorate my forest but it may also be suitable for you beach : you can do rocks with ROCKFLR1, ROCKFLR2 and ROCKFLR4 (ROCKFLR3 is too red blood, he imitates not the rocks, I would not recommend it.)
Textures:
Sands with different floors: DCYELLW, such as sands mentioned above, sand in wall version.
To color the walls of rocks ... ROCKWLL 1, ROCKWLL2, ROCKWLL4.
For water:
You have the choice between LWATER (light blue) and BWATER (dark blue).
It's a bit stupid, but the walls of water, if you use LWATER, use LFALL. Similarly, if you use BWATER, use the wall BFALL .
Hope to have you help.