I run a 47 ltr ARB fridge.
If you only keep 6 or 8 cans/bottles of drink in the fridge and replace each cold drink you take out with a hot one, it's more than big enough for drinks and food, for a few nights/days away. Unless you're real thirsty or a big eater.
I chose the 47 ltr more for its external size than anything, as the 60 ltr fridge takes up a lot of precious room in the back.
ARB 47 ltr :- EXTERNAL DIMENSIONS H508mm x W380mm x D705mm
ARB 60 ltr :- EXTERNAL DIMENSIONS H428mm x W450mm x D845mm