I know what you meanabout it being hard. My son is on a gluten free/ Cassin free diet (due to Autism) but i have found a few cook books that have helped that cater to kids with allergies. Also there is a website that sells food for people with food allergies. i would google it i don't know thw name off hand. ( i think it is miss Rice foods something like that) (i will tell you it is pricey) but it's worth it. Also there is a store in Oviedo that sells food for children w/ food allergies ( 2 mom's w/ children w/ Autism as well).
As far as for the Dairy Part Rice milk taste almost like regular milk as well as goat milk (but rice is easier to find) Also Pricey. Some stores even Walmart carries wheat free flour and breads you just have to do alot of reading.
But i would look online at amazon for cook books for food allergies ( I found the books looking for books about Autism)They have real good recipies EVEN CHICKEN NUGGETS!!
Hopes this helps