Hi Sarah and Olivia,
Sarah you are a champion for offering such sound and considered advice to one of our community, thank you!
I think Sarah has covered off the main points, all of which I agree with.
My suggestions to add:
It can be quite exhausting for you to spend a whole day with clients (depending on your personality type of course!) and can also be exhausting for them. I would suggest perhaps breaking up the day into 2 different half-day trips, and then the consideration of lunch isn't such an issue.
Personally, I like to keep the popping of a bottle of champagne until the project is complete. Stopping off for a coffee with the clients (or asking your suppliers to put on morning/afternoon tea) is a nice option.
I think I might get Sarah to organise my next shopping trip, complete with maps and schedules... Incredible, well done you!
Good luck with this exciting project Olivia.
Cheers,
Andrew