We will be taking the train to Windsor, do we need to buy tickets in advance? If not, at the station, they don't use oyster card or tap & pay, correct?
Thank you
You do not need to buy ahead. And YES, you can tap and pay with a CC but you can't use an Oyster. There are also big signs at the Windsor station cuing you to "tap out".
This is assuming you are going to the main train station, Windsor and Eaton Central via Great Western Rail from Paddington.
https://www.gwr.com/your-tickets/smart-tickets/contactless-payments
Tammy - where are you staying in London?
There are two routes from central London to Windsor. As Pam says one route runs from Paddington to Windsor & Eton Central - it's slightly quicker and you can pay by contactless card but you do have a very simple change at Slough to get there. You can also use this route from any Elizabeth line station across central London - you just need a train going towards Reading.
The other route is from Waterloo to Windsor Riverside. You do at the moment still need to buy a ticket for this route although there is no advantage in buying ahead of time. It takes a little longer but is a direct train and the destination is Windsor so you can't miss your stop! This route make more sense if you are staying nearer Waterloo than Paddington.
Thank you
We are staying by the Tower of London but we are looking for a gluten free tea service to go to before we hop on the train.
Depending on your schedule you could consider having Afternoon Tea at a location in Windsor. I see the Castle Hotel's restaurant, Leaf, has a GF tea.