Alternate pasta with other dishes that absorb water. Save the spaghetti water and use that when cooking your rice (instant mashed potatoes, oatmeal, grits, soup).
Also, I have a "30 day supply" of MREs, which consists of 90 MREs. At one per day shared among a family of four, that can add a lot of variety and nutrition to the other stored food for three months.
I did a test and soaked pasta in water over night. It expanded as if it had been cooked. Rice did not. By soaking instead of cooking you can reduce the amount of water and no cooking fuel is needed.