Try dried pasta & the sauces you get in jars or tins. You can also get tinned "breakfasts" usually consisting of baked beans with added reconstituted "stuff" masquerading as mushrooms, bacon, burgers etc. Cheese is something else that stays OK for a few days, especially Baby Bels. Bread of course - use margerine rather than butter as it takes longer to go off and don't forget the jam and/or peanut butter. Get UHT or sterilised milk rather than fresh, it might not taste as good but you won't get the problem of waking up in the morning & finding your cuppa has lumps in it.
DON'T FORGET THE TIN OPENER!!!!