Hi
We are like you 2 adults, 3 kids. We have towed at 85%, 93% and now about 81%. To us it doesn't matter the ratio, we still pack the same. You just have to be a bit more careful if over 85%.
Nose weight is very important.
The awning, poles and groundsheet goes in the back of the car. The picnic table and chairs goes in the back of the car. A picnic for the ( long) journey goes in the back of the car, as do some travel bags with clothes and travel blankets (fleece blankets). A change of clothes for the kids and T shirts for us go in a separate travel bag which is easily accessible just in case somebody is ill on route.Tissues, plastics bags, fresh wipes etc, are readily accessible. We have a first aid kit readily accessible in both car and caravan.
On long journeys I put some basic food in the caravan fridge (its near the axile of our caravan) and the low cupboard in the caravan near the axile. Our spare wheel is under the caravan in our current caravan, near the axile., in our previous caravan it was carried on the axile in the caravan. We put anything heavy over the axile of the caravan eg kids scooters, wind breaks, awning pegs etc. We travel with food for 2 days to cover the first 48 hours arrival on site.
Waterproof coats for kids and us need to be easily accessible. We also have fleeces readily available. They tend to travel in the car.
We aim not to have very much near the kids feet when travelling, they each have a small rucksack with their own things for the journey, eg books, games, activity kits etc. Our kids are very good at travelling. On long journeys, coming home, we do use an in car DVD player with a DVD the kids have not seen.
Kids toys/ gear can weigh a great deal more than we as adults think. I use folding crates to carry the kids toys, these can be placed over the caravan axile, also useful for storage in the awning. We are quite strict on this, as were my parents when I caravaned as a child. We, as adults like to read books, its surprising how much they weigh, we aim to put them near the caravan axile.
Hope this helps.
Annette