Milk for long road trip?

I know this is probably a dumb question but I know that after baby turns one (my baby will be 14 months on October 2nd) they need the fat and stuff that’s in whole milk. I don’t want to bring whole milk on the road with us and the little bottles at gas stations are kinda expensive when a whole gallon is like $3 so I was just wondering if it would be fine if I just buy a thing of formula for him to drink since I already know he likes that kind I’ve tried him on a few toddler formulas and pediasure and he didn’t like any of it he will only drink sweetened soy milk (I bought it on accident once) and sometimes almond milk and he will drink whole milk fine. It will spoil in the car for 7-8 hrs. I’m thinking my best bet would be to just buy a can of the formula he used to drink and let him drink that. He is over 1 and still wants a bottle of milk every 2 hours ( sometimes sooner) he drinks 8 oz and finishes it.

Also what are some good snacks for baby on the go I’ll be in the back with him the whole time he will be eating because my anxiety won’t allow me to leave him while he eats. Thanks in advance❤️