I hate leaving my chins too. It's always so traumatic....for me, I don't know if they even notice I'm gone but it sure feels like it.
I would not let anyone take your chin out of the cage. Too much can go wrong.
I would definitely have your mom come over and let her do the routine with you watching. Don't just do it yourself with her watching, actually let her do it.
I like to encourage my pet-sitting friends to spend as much time at our apartment as possible, because I think the chins just like having someone around. I always tell them to stay and watch a movie, and I like to leave a 6 of beer to encourage them to sit around for a bit
I have a detailed "Chin Care" form on our computer I print out every time we have to go away, and I leave it by the cages. It starts out "Congratulations on your wise decision to look after our chinchillas...."
It has every detail of info I could think to put, including my friend's phone number (who also have chins), a vet, and I even include this message board address in case they need a question answered quick!
As for putting a bunch of food in the cage.....that's actually a great idea I never thought of before. You will only need to put 3 days worth, cause you'll be back on the forth day, and chins won't overeat. As long as they don't pee in their food or anything, that's a good idea. Or one of mine has a new trick where he likes to scoop all the food out of the bowl and throw it all over the shelf. That's annoying
. Hopefully your guy doesn't do that.
Good luck! Bring a picture to look at when you miss him!