We got a NOCO brand jump starter two years ago, and I’ve been happy so far. Gives us a little extra peace of mind when we stay at a remote cabin up in the mountains. Not many people passing by to help with jumper cables, and AAA doesn’t come out on the gravel roads. The best part has actually been how easy it is to help out other people with a boost. I’ve always been a little intimidated by the jumper cable routine, but this battery jump starter is very easy to use. Last summer we were driving through Wyoming on I-80, and we stopped at a rest area to change drivers. A young woman approached us and asked for a jump start, saying that she’d run down her battery by leaving the car accessories on while taking a nap. Even though I was in a bit of a fog after driving a couple hours through thunderstorms, I was able to grab the jump starter out of the back, hook it up, and get her going in just a few minutes. (And these battery jump starters are a good preparedness gift to any young women in your life, if you don’t like to think of them having to approach a stranger in a rest area for a jump start. We were probably a good choice to ask, as we have the “friendly grandparent couple” look, but you never can tell.)
You seem to have thought through your situation fairly carefully and realistically. I have just a few misc thoughts. While staying home is clearly going to be best for most situations, I think that it’s great that you’re packed to leave if needed. Even if it’s not a SHTF situation, you might need/want to leave your house under a smaller, more localized “emergency.” For example, if there were a local, but extended, power outage, or a furnace or plumbing failure in your house, it might make sense to go stay with a relative. In those cases you’d have some time to pack, but it’s hard to be efficient with a house full of high-need people, and you’d be grateful that you’re ready. If you haven’t already done so, it would also be really worthwhile to work out your family evacuation plans in case of a house fire. If you woke up in the night to the smoke alarm going off, do you and your husband have a plan for who grabs the kid, who helps the parents out, where you meet up outside, etc.? For quickly getting the parents out, you might consider having lightweight folding transport wheelchairs available, if you don’t already have them. Those would let you quickly push them out of the house, rather than the glacial pace of moving with a walker. And, thinking about transport wheelchairs, they would not be sturdy enough to trek for miles in a bug out situation, but they would let you move away from your immediate neighborhood if needed. They also could be carried in the car, and would be useful if you did have to go to a hotel or shelter, as they would give the seniors a safe place to rest and hang out (kind of like a stroller for the toddler).