having the keys to your new place IS a dream!
Book a cleaner- let them do a deep clean of the new place. Saves you time and stress, and you can concentrate on your "old" home.
Bring beddings , toiletries, essentials (loo roll , hand soap, hand towels etc) and make sure light bulbs are working
all already there when you arrive and you don't have to find in the new boxes
Pack separately, and stick in the car:
your valuable, essentials you needed until last minute (like a kettle, your toothbrush. pyjama...)
How much downsizing are you doing?
Make a decision about furniture first-and quickly. Keep or get rid if it doesn't fit?
Downsizing tend to mean less room but worst, smaller rooms, you need to be practical
The removal company will need to know exactly what you are moving to give you the correct price (if you have a grand piano and you are getting rid of it , it makes a massive difference. That's an example)
Then get boxes and bubble wrap, and get started, be RUTHLESS. No need to move clutter.
Label, label everything, put number and name of the room on all boxes, ON ALL SIDES, and keep a pad with the full details
It really doesn't need to be stressful, it's just tiring.
The problem with someone else packing, is they pack everything, you don't know where everything is, and they pack all your clutter so you end up with too many boxes, paying too much and having to get rid of crap at the other end.
No need to do that