I suggest you and your family sit down and agree on actions to be taken under different circumstances. Most H/T (handi talkies) are line of sight like you mentioned but if one of you is in an area below the level of the transmitting H/T you will not communicate.
Come up with a meeting place that is central to your work area, your wife’s school and your children’s school. Once you do that then get there when you must. Do not run around trying to hook up with others. Under no reason leave.
You are correct about transmitting on HAM frequencies after SHTF. The large portion of repeaters may have back up batteries but that is only temporary. The ones in my area are such that they also have access to back up generators.
Here is a url that will take you to a website with resources for the UV-5R.