In reply to marsbar:
> Why a blizzard blanket if you have a shelter? What will you do if your mobile has no reception. Knowledge is more useful than equipment.
The OP refers to taking young children out walking and climbing. As a parent you will already have got basic plaster sticking experience which is going to cover anything that could be resolved by walking off.
So we are only talking about something which means the casualty cannot move and you need to get MR. In the majority of rescues involving groups, particularly DoE ages, we find a significant numbers starting to suffer from hypothermia and seriously so if winter. Kids get worse (and better) a lot quicker than adults so the first priority must be to shelter everyone.
Since you have to call out MR then you need a mobile phone. If there is no signal then someone has to go until they get a signal. Unless you are going to walk to a phone box or house there is no choice you must have a mobile phone. The phone, if a smart phone means that we call also SARCALL you to locate you.
The casualty is unlikely to be able to move much, otherwise they may be able to walk out, so they are going to get cold quickly even in a shelter. A Blizzard blanket will keep them warm, you can get them in it without making any injuries worse and you can check them. You do need to insulate them from the ground with any sit mats, bags etc.
The only thing you haven't done so far that maybe a First Aid course would prioritise is CPR and Traumatic Bleeding. Realistically CPR is not going to achieve anything without AED, Oxygen and BVM.
But you have protected the group and the casualty and called or sent for help.