JS,
You need to adjust your meal planning for this excursion. Our little coach is currently (DW has assured) provisioned for about a weeks worth of boondock time. While that may just be for two of us, the size coach and the need to feed teenagers can still be accommodated with proper planning. Start here....
Make a meal chart.
Decide what you can replace.
Powdered milk gets better if mixed the night before.
Canned vegetables can replace fresh in may cases.
Pasta is great for filling appetites.
It can go on from there almost endlessly.
Find a used book called "The Two Burner Gourmet". There may be others out there as well, but we knew Terry.
Remember, "Tin Can Tourists" was not about what they lived in, (even "canned ham" trailers didn't yet exist. It was about how they ate.
Matt