I've sailed Princess numerous times and we always hold on to one of the room service trays to use to bring things back to the room from the international cafe.
The room service tray could also be a close friend to us too :) Trying to carry a few coffees and breakfast items up from international cafe without a tray is a challenge.
That's a bit strange having no trays in the buffet. Is it just on that ship or all Princess ships? I was a bit surprised, too, that you have to pay to use the laundromat. It's interesting to see how different cruise ships do things differently. Thanks.