I'd prefer not to take a real measuring cup with me. In the past I've cooked oatmeal just fine by eyeballing it. I put two fists worth of stone ground oats and then an individual sized soy milk in the pot and cook it. But this time I'll also be cooking stuff like quinoa and that seems to want better measuring if you want fluffy vs. mushy.
I've thought of drawing calibration marks on a clear water bottle. But I don't recall seeing those at my LBS and I'm leaving for the mountains Saturday morning.