I've tried the Chef Boyardee canned macaroni and cheese, and found it fairly nasty.
Fortunately, I only bought two cans (@ $0.85 each), so I didn't waste a bunch of money stocking up on what I call "Donner Party food" (if it's a choice between the above-mentioned Chef Boyardee canned macaroni and cheese and anthropophagy, I'll tighten my belt and put off the choice for as long as possible
). The moral of the story, of course, is to taste-test before stocking up on LTS food.
If your LTS foods are primarily aimed at short-term emergencies, such that you're not deterred by the costs of freeze-dried backpacker meals, I've taste-tested the 480-calorie Enertia Three Cheese Mac
. It was pretty good, though I'd probably opt either to add the TVP "ham" bits in with the pasta (for extra rehydration time) or to save them to add flavor to some other meal. At an MSRP of $4.99 (I bought mine at Tucson's Summit Hut
for $4.95), it's a reasonable deal for a solo diner. One flaw with Enertia meals is that they tend to come with multiple sub-packs inside the main package, which can be messy when adding the sauce packet to the mostly-rehydrated pasta in the main package. Meanwhile, Mountain House offers a 470-calorie macaroni & cheese entree
, with an MSRP of $6.40 (available at Sportsman's Warehouse for $5.99
OTOH, if you're looking to stock up for the long term, freeze-dried meals are not cost-effective. I've found that "deluxe" mac-and-cheese boxed meals (the kind with a foil packet of cheese sauce, instead of powdered cheese sauce) seem to work pretty well. Just be sure to knead the cheese sauce packet before adding it to the macaroni (I learned this lesson from MRE cheese packets).
WRT storing Velveeta, it has a labeled shelf life at room temperature of about six months; you could probably stretch that considerably through some combination of refrigeration and choosing not to hold Kraft Foods liable for your eating Velveeta after its labeled shelf life date. Jerry has some additional insight on cheese storage, as posted above.