I've spent a ton of time to make my brakes work the best they can, and they do. I can lock them up if need be, but I typically drive as if I can't, in other words, I give plenty of space to cars in front of me and always assume that someone is going to give me a reason to slam on my brakes.
I've also added HD sway bars and better springs to help with the handling and it can swerve better than a stock van with less risk of a rollover.
I've seen a bunch of vans out there loaded to the gills with all kinds of "stuff" and I don't always get the impression that they've thought about weight distribution and how it affects handling.
Did you think about weight distribution when you loaded the van, keeping heavier items down low and lighter items up high? This comes into play with regards to cargo pods and stuff that is your cargo tray and on your rack.
Weight behind the rear wheels can affect your rollover potential drastically, so it's best to avoid heavy items to the rear, and always keep weight as low as possible.
In the case of a rollover, is your cooler or other heavy items secured in a way to prevent it from flying around and hitting your passengers? You'd hate to see one of your children get hospitalized because of a head injury caused by a box of ?? that was laying on the floor. It could happen. My Engel Fridge weight about 50lbs empty. I was sure to strap that thing down to protect my son who sits just a few feet behind it.
Enough of the darkness and doom.