Hi Tracy!
Thank you for visiting the Moms Panel!
What a wonderful surprise for your daughters to have afternoon tea at the
Garden View Tea Room at Disney's Grand Floridan Resort & Spa. They will enjoy a real treat! Being British myself, I love afternoon tea, and I am sure you will have a lovely time there.
From Disney's Port Orleans Resort - Riverside, you will need to take a bus (quickest option for this journey), or a boat, to Downtown Disney and then transfer to another resort bus for Disney's Grand Floridian Resort & Spa. It is generally recommended that you allow 60-90 minutes for the total journey time, from your resort room to your dining destination.
I am sure wearing a sun dress would be the perfect option.
Enjoy your magical afternoon at the Garden View Tea Room, and if you have any more questions, please come back and ask me - I would be happy to help you plan your magical vacation!