Our families are pretty similar. At the time of travel, we will have 16, 14, 13 y/o boys, a 9 and 2.5 y/o girl and 14 month old boy.
My parents are also coming to help out! And we're all hoping for the free dining. My teen boys are athletes already over 6' 170+ and can literally eat all.day.long.
We are planning on traveling in early Dec '17 (flexible dates to try and snag free dining).
I priced everything possible- renting DVA points, 2 rooms at value & mod, suites, cabins, etc.
The best value for us was free dining & 2 rooms at Coronado. A value resort would only get us the quick serve dining & then we would need to upgrade or pay out of pocket.
I planned each meal, checked the menus and priced it out to be sure lol! I included everything - Every penny we would need, from gas to spending money to tips! Our final price is $7550.
-The cheapest DVC rental was about $1500 more (value 2bdrm AK, the standard 2 at AK was $1900 more)
-The value & mod came out equal, factoring in upgrading the free dining, and the value was actually more expensive if we paid out of pocket for the difference in food
-offsite was about $1000 more since we had to pay for food (even with discounted tickets and not hopping)
-room only was more, even with a 20% discount (not even sure if that would be out just checked in case)
I should note - we don't camp so I didn't check out RVs or the campsites! And we aren't willing to do more than snacks & coffee in our room on a Disney vacation, so if you are, your numbers could be different!
HTH