You'd be surprised on how you can manage when push comes to shove... We've done many trips with just a 40l Engel.
Two questions for you:
How many are you packing for?
Have you got/started a food list?
Anyway, agree with the fellas about cryovaccing meat as a must (either done by you or by the butchers).
Like most swaggers, we freeze the meat first (if possible) and then, if you just use your fridge as a 'fridge', let it slowly thaw. Even like this, red meat will be easily be good for 2 weeks. Chicken meat gets eaten first as a precaution.
Some other pointers:
Find the perfect size 'decor' type containers to help pack the fridge. We freeze the meat at home in them first, then transfer to the fridge. Helps stop any leakage as well.
Get used to pasta and sauces without the meat
UHT milk packs
Small juice tetra packs
Butterless sandwiches
Canned tuna for stir throughs
One out, one in beer/drink rotations
one word... SPAM
Try the packing once or twice and it becomes easier each time.
LJ