listening in for ideas.
But BM is fine for 4 hrs at room temperature so normally when going out I just take in a bottle and maybe put in a cool bag so stays cooler for longer.
In terms of NF the reason i stopped EBM was because of similar reasons, 1 it was a hassle to get the water warm, milk warmed etc and by then DS2 would be crying loudly and waking DS1, so I do a DF with EBM and NF is BM. Also saves having to express in the middle of the night!