Figment I'm sorry to hear about your mum. What an emotional time for you right now. There is nothing wrong with not being with your mum on Monday, or with your family if she has passed. Of course you want to take your dd and see her settled in so if that's what you want to do, it's fine.
Regading the packing, all she needs is enough to see her through the first two or three weeks and then, hopefully, you will be able to take down anything else she needs. I'm sure a treat box will be appreciated as a late gift, just as much as an early one (maybe even more so once the novelty of freshers has died down).
Is there anyone else who could do a bit of shopping for you over the weekend if you give them a list? Ask you friends. I would be more than happy to help my friends out at a time like this.
What last minute things do you need help with? Your dd can sort most of them out herself. Hope you mange to get some sleep, take care x