The snake should be fine for a while as far as the food is concerned. It could easily manage a few weeks without much impact. The more pressing situation is temperatures. If it is too cold the snake could contract a respiratory infection. Do you have a regular heating pad you can set it on low and put it on the floor near the opening you suspect it is in? Also try putting a live mouse/rat in a one of those critter keepers where it can be closed but has plenty of holes for scent. Did you look to see if it may have gone up under the kick plate of the cabinet? If there is a hole under there it could just be under the base of the cabinet. I hope you find her soon. Good luck