We use ice cooler for beverages or things that don't mind a little moisture and water jug with ice for drinking water.
Do the same thing as others have mentioned. Put blue ice packs in freezer to "hold" temp when traveling and help with moderating temp changes when fridge is opened.
To a large extent we try to avoid foods that need cold storage or pick them up as needed.
Had a 12 volt compressor fridge in the past and really liked it, with
solar being as reasonable in price as it is I would think that is an even better option today.
Those 12 volt portable coolers are rated by the temp differential they can generate against outside temp. 40 degrees "cooling" sounds good unless outside temp is 95 degrees. So that rating is something to look for when puchasing these.