Hi there, good luck with your goose, things always happen when the vet is closed eh. I would be very gentle with massaging her crop, as it is likely to be very uncomfortable, and the goose sounds not too happy as it is- so any extra stress will make things harder for her.
Keep in mind it may not be an impacted crop, it could be a growth or an abscess etc. I would keep her warm and quiet with food and water or whatever she needs.
Talk to your vet asap, about what you need to do when you are at home with her.
I suggest that if you need urgent information that you email the duckman - in NZ. He has set up a centre for injured and orphaned waterfowl and was very helpful when i emailed him a few weeks ago asking advise about handrearing a paradise duckling. He looks after 300-400 birds a year. If you do email him, let him know you are in the UK so he emails rather then says ring. email
[email protected] All the best.