I have made cereal both ways. Sometimes I make rice or oatmeal flour using the blender and then just cook enough cereal for 2 or 3 days. Other times, if we are eating a grain he would like, I just cook a little extra and blend it up in the blender. I definately freeze some of the extra for busy mornings. I have given DS some of the Earths Best organic fruits that I can't get fresh, and then use those jars to store frozen servings of homemade stuff. You can just thaw a jar at a time, just put in a bowl of hot water for a few minutes or heat it on the stove. They leak, though, so if you are going to carry along some homemade food I would use a tupperware. I found some that are almost exactly the same size as babyfood jars, they are perfect for carrying his lunch and don't leak in the diaper bag!
My favorite baby food prep tool is a Braun handheld blender, I bought it for $15 at a kitchen store. You can blend up practically anything in a cup without having to mess up the blender or make a huge portion.
Food on the go? Banana, just put some in a tupperware and mash at mealtime. Avocado is the same. If you have something that doesn't leak, you can really take whatever you want.