My tips are similar to Cricket. We have moved twice in the last 18 months so I feel like I am an expert!!
Get those boxes and start going through everything now and pitching everything you don't need and packing the things that you can. It will be much easier to pack if you have "pitched" first and it won't take so long.
Definitely have your children looked after for some of the time and try also to get them looked after while you declutter in the next few weeks.
Be prepared to have takeway on those 4 moving/packing days. Using the kitchen is impossible as half the stuff is packed and you won't feel like cooking.
Be prepared for a demoralising time when you are about 3/4 done and it still looks like you have about 10 trips to do.
If you lare not moving to far and you can do it my preference is to unpack as things arrive so that you don't end up with a million things to unpack as you are usually over it by then. and that way it is not so important to label boxes as you just unpack them as they turn up. so you could have your mum finishing packing at the old house while you are unpacking at the new.
Pay someone or get your mum to clean the house you are moving out of, as the last thing you will feel like doing is go back to clean it.
good luck