We'll be getting off as you are getting on.
Just yesterday I asked about semi-formal nights. (See thread "Grand Prancess - Semi Formal Night) and have been advised that even though the documents say there are semi-formal nights that they have dispensed with them. Two formal nights and the rest "smart casual".
Formal nights are generally tuxedos or dark business suits for men and fancy dresses for ladies. (I'll let some of the ladies be a little more specific about what fancy dresses mean.)<g>
We're looking forward to a great cruise. Hope you are too.
We just returned from the Grand Princess last night.
Two formal nights is correct and I agree with the comments above that women and men do get dressed up, however suits are OK if you don't have a tux.
The Semi-formal night has been replaced by a Casual/Island attire night. The Island attire (Hawaiian or Island shirts) is very popular and there is an Island night deck party at the rear of the ship after dinner that night.
We just came off the Grand 9-23 sailing and had cabin L227 (just a couple of doors down from yours). It was an awesome location, we loved every minute of it. Never heard any noise and it was wonderful to be so close to the pools and Horizon court. Also the elevators there are faster then farther back on the ship. Have a great time!