My kids drink Almond milk. Both get tummy aches, constipation, increased reflux, rashes with cow's milk. Soy gives my daughter the same upset tummy/constipation as cow's milk and my son was allergic to soy. he seems to have outgrown it but it was not a pretty sight when I tried to give him soy formula so it wasnt a surprise that his allergy testing showed positive. Anyway doctor said not to bother trying goats milk so my DD started on rice milk. after trying all the rice milks for my son with any kind of flavoring (he is strongly opposed to chocolate drinks) we ended up with almond milk. So to make it easier for me they both just drink it. My son only drinks Blue Diamond's Almond breeze regular or vanilla and likes it with strawberry flavoring. Occasionally he has had Nesquick Strawberry readymaid from the grocery since I keep trying milk to see if they are outgrowing things (thankfully they are getting better and better with it) NO OTHER MILK BEVERAGE crosses his mouth he is so picky.
All that to tell you that I'm pretty familiar with looking for alternative milks in stores and carting it around with me. The packaging being similar thought I could maybe help you with finding / packing them. All of the grocery stores around me have atleast one mostly 2 (some more) different brands of both soy and rice and those will all be in various flavors on the shelf. We have 2 Publix grocery stores and one has a much bigger selection of them than the other. The one with less has the Non- frige ones (and juice box size) with the organic foods section. The other one is in an odd place in the middle of the store I think on the aisle with the canned fruits. Kroger is with the health foods but all the other stores I find it in the oddest places. It may be with the health foods but they have such a small health food section that you hardly see it. Food lion stocks like a total of 8 boxes of special milks. Easy to miss it. So anyway, the first time I found it in each store I had to find an employee and ask they usually didnt know what in the world I was talking about and had to ask someone else. They mostly come in quarts which I find great for traveling, i end up sticking them here and there throughout the car. I'm not sure what all has been already posted. I try to buy when I'm near a smaller healthfood grocery. NOT the whole foods market, small healthfood store like you see in a mall or something, or other chain large healthfood store. They seem to have higher prices than the grocers. this small store I buy from has prices as much as $1 less per quart and I can buy by the case(12 quarts or 8 half gallons) to save more.