Hello, I had this idea as well, and am trying it out this weekend. I fed the cats this morning (Friday) and left enough dry food, water, and litter to last till Sunday afternoon when I return.
I put the food in little plastic bowls with water mixed in (that's how I always feed the wet food, to both make sure they drink more water, and so the bowls end up with less caked on hardened food), and froze them solid overnight.
Worrying it might thaw before tonight or tomorrow morning, I took the added precaution of sliding the little bowls into an ice pack sleeve (for a wine bottle) that I have. I know my cats smell the food in there, and I know they'll be able to slide it out. This could either be awesome, or I'll come back to a bunch of smelly hardened food.
I will let you know how it goes. :P
And you can definitely leave a cat home for a couple days unattended, especially if it has company of other cats! They are not babies and they are not dogs. They're very smart and they know how to ration their food, and usually they're pretty good about not killing themselves.