Hi MrKlaw,
Can you confirm the times of travel in each direction?
I need to correct some errors above. Travel between Chiswick Park and Slough is subject to an evening peak between 1600-1900. The confusion is because it is off-peak the other way. The 16-25 railcard is valid at any time, but there is a £12.00 minimum fare when used before 10am. You can use contactless at Windsor and Eton Central. The touch pads are at the end of the platform in the shoppping area. There is a sign by the side entrance next to where the trains stop pointing you in that direction.
The contactless fares are valid on either EL or GWR, but they are adult only, no railcard allowed.
There is supposed to be a return ticket from Windsor and Eton Central to London Underground zone 3 for £13.45 with railcard discount, but I can’t get any websites to sell it. I’ve asked for assistance from a contact. If there is a ticket office at Windsor then they might know how to sell it, or alternatively the ticket office at Slough may be able to help. I think that is the cheapest way to do things.
If we can’t get that fare to be sold then your daughter is already doing the next best thing. Use the paper ticket from Windsor to Ealing Broadway and contactless for the tube. She needs to touch out by exiting the gateline at Ealing Broadway before using her ticket to get back in on the way home. In the morning she can use the pink readers because they will start a PAYG journey, they just won’t end one.
The start time of each journey would still be useful, especially if it can be outside the two peak periods of 0630-0930 and 1600-1900. That is, might she start early or finish late to be able to use off-peak fares.