First, my prayers are with this man and his family.
I have had to deal with the situation of shepherding kids into the van for several years now and I am always open to new ideas. Let's keep this thread going with positive input.
When we go out, my children and I put our shoes on at the front door which has a storm door on the outside of it. With the main door open and storm door locked, I can get a good view of the front yard, driveway, vehicles and a good bit of our street. We have had some recent armed robberies in our neighborhood lately, so I am taking more time on this initial observation/awareness issue. If things look good, we go on. And my children know that I keep a weapon on me and to be alert for strangers and exercise some caution on their part. (God, please let them have learned those lessons!!!!)
For myself, I'm fortunate that three of my four children can walk to the van and get themselves buckled in their carseats. This frees my mind and hands up tremendously. The baby is carried in my left (non-dominant) hand and my right hand is always free. If I absolutely have to carry anymore things like diaper bags, coats, etc, the non-essentials (aka non-children!) are carried in the right hand so they can be dropped aside quickly and without second thought. I have trained myself to get the baby strapped in mostly by feel now, so I can look around and be aware of the other kids and our surroundings. Our routine for getting into the van is pretty rigid around here, too: everybody goes to the van and gets in their seats; nobody runs around or jumps in the front seat or anything like that. This allows me to pretty well know where my children are and the most likely "open areas" for good shooting, should that happen.
Children loading/unloading is more difficult out and about, but we still try to work things the same way. The one constant is having my dominant hand free for the most part. For you guys that do the same, doesn't your left arm get tired!
In general around here, we aren't very flashy people. I leave my nice lawn equipment locked up when not in use, we put our big boxes (tv, dvd players, etc.) in the trash can and not out in plain sight. Our vehicles are plain jane - beat up work truck, average mini van. I also tend to be somewhat of an abrasive and stand-off-ish person concerning strangers coming onto my property - salesman especially! I try to make eye contact and take notice of suspicious people and definitely do not let anybody near my children or vehicle or inside my home unless I know them.
As far as toolset goes, I have changed firearms a few times, but I always keep as my primary defensive arm a full-sized pistol, carried either IWB or OWB strong side hip and a back-up in the ManBag (Maxpedition Fatboy) for consistency. The draw and presentation of the firearm is something that has been practiced many, many times and will continue to be practiced.
These are just some things that we do around here to make life a little safer. I have been carrying a firearm and corralling kids for six years now (which in no way makes me anything of an expert!) and my methods have changed and been modified as needed. I hope this helps somebody out there on THR. Most of the advice I have given has been learned here in the past.