I am not a parent, but I wasn't a kid that long ago, and I was raised by a single parent for the latter half of my childhood. Do bear in mind though, then when my father left, I was 10, brother was 11, and my sister was 14, and we were all fairly mature for our age.
For my family, it came down to a deep amount of trust from my mother, despite her paranoia.
Since my sister went to high school while my brother and I were in elementary school, we didn't have the luxury of her escorting us, as her school was across town from ours. Essentially, my brother and I were given lessons on how to deal with strangers, people offering rides, etc, and my mother trusted us that we would follow them. Bearing in mind this was a small town, we were allowed to walk to school, a whole 3km walk (with backpacks... made excellent practice for future ruck marches
)
A quick google search reveals Esq is about 3x as large as the small town I was raised in. If you're too paranoid about your kids walking to and from school, you should be able to befriend a neighbor who has kids who go to the same schools, and you can arrange for your kids to ride with them. Just make sure your kids are up on time to be ready for rides, else you risk annoying friendly neighbors.
When it comes down to it, make sure your kids know what to do when SHTF for them. I was always told:
1) If you're out walking and need help, run to a house (preferably a block parent) and start banging on the doors.
2) If someone tries to take you, scream bloody murder.
And for at home:
1) If it's a fire, someone's dying, or something else equally bad, dial 911.
2) If it's not that bad, senior sibling's discretion. In the event of disagreement, call mother at work, memorize the number. Please don't harass (parent) at work because sibling x and sibling y can't get along for 5 minutes.
Keep it simple, don't expect them to memorize an operations manual on daily routine.
We also had strict rules for keeping in check: We were required to call our mother once we got home from school. If you want to do anything after school, go home (optional), call (mandatory), and get approval (also mandatory), or else paranoid parent with car/law enforcement/search and rescue will be hunting you down (it took me a few times to get into the swing with this one). If we were going to be late (ie: detention, etc), a call was customary.
Now, bear in mind this was before cell phones became prevalent. Though I have a tendency to believe that cell phones + paranoid parents = bad for kids, I still think they have merit. You might want to check this out:
http://www.telusmobility.com/on/pcs/handset_lg_1000.shtml
One of my younger cadets had one of these, the preprogrammed numbers for him were:
Emerg: 911
1: Home
2: Mother's work
3: Father's work
4: Trusted friend
Kid friendly, and they can't call numbers that aren't programmed in, and also 1-touch emergency is good for panic situations. One of these for the 3 of them should at least allow you to call them and get LOCrep, SITrep, etc in case of excessive paranoia, and allow them to contact you in case of emergency.
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Essentially, when it comes down to it, keep your kids in touch, but trust them. Be adaptive, and don't be afraid to ask for some help along the way. Your kids may be young, but they should be more than capable of keeping an eye out for eachother.
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Again, I am not a parent, so grain of salt goes here. This was the doctrine that I was raised under, YMMV.