I hear you about cramping. I've had problems with that my entire life, and it's rough. During a tennis match last summer, I started cramping so badly during the last set that I couldn't unclose my hand enough to take the racquet out of my hand. The cramping problems followed me to cycling, to the point where I once fell off the bike because my quad tightened up when I stood out of the saddle, and wouldn't bend again when the fixed gear forced the pedal back around.
I've taken to spiking my bottles with a teaspoon or so of salt. It makes the water or sports drink taste weird, but maybe it helps. Also, Clif makes a margarita flavored Shot Blok, which is spiked with a lot more sodium than their other blocks, which they call a "cramp buster." I've started eating these on my rides in addition to the salted water. But I haven't had a chance to try these two out during summer. Although I'm not sure there's anything to prevent cramps when Louisiana's summer starts really rolling.