sounds like a good idea you have started here. a couple pointers though, medical research has shown that keeping blood sugar extremely stable after surgery decreases healing time. this is why post op open heart patients go on insulin iv drips even if they are not diabetic. so stay away from anything that contains large amounts of easily processed sugar. you dont want to cause sugar / insulin spikes. when working as a trainer i used to have a shake in the morning made of yogurt, celery, spinach leaves, blueberries, strawberries, and a bannana. you get most of your daily vitamins that way. you might also look into some protein shakes. or just mix pasturized liquid egg into you shake, you wont even taste it. good luck with your surgery, hope something i said was useful.
p.s. im sure you already know, but stay away from real mre's those things are not healthy for prolonged consumption.