I made vegan s'mores for the first time too. I have eaten Sweet & Sara's s'mores and love them!
Instead of Butter:
Sauté in water or vegetable broth, use lemon for dressing, or switch to vegetable margarines and oils.
Instead of Ice Cream:
Try frozen desserts like Soy Delicious, Tofutti, Rice Dream, fruit sorbets, and ices. You'll never want to go back to the cholesterol and saturated fat of ice cream.
Instead of Milk:
Try chocolate, vanilla, almond, and plain soymilk. Excellent for cooking, on cereal, in coffee and hot chocolate -- use it any way you'd use milk. Comes in low-fat varieties, too.
Instead of Cheese:
Check health food stores for soy cheese, which is great on pizza, on sandwiches, and in sauces. You can also make a great, creamy "cheese" sauce using nutritional yeast flakes.