As you cross the Awatere Valley, you will see Lake Grassmere on the left. This large shallow lake is best known for the salt extraction facility on the west side of the lake. From SH1 drive down Kaparu Road for the best views of the lake and salt facility. The ponds by the road are filled with seawater which evaporates, leaving the salt behind. What you will see depends on the stage of the process, but it is interesting.
Then take Marfells Beach Rd around the south side of the lake to the Marfells Beach. If you stop after the road swings to the north and before the beach, you will get a good wide view of the hills and mountains to the south west of Clifford Bay. Note that there is no real easy access to the lake itself.