I will be spending just over a month in London in June and looking at a few day trips. With the possibility of one or two overnights. I know often it is much cheaper if you book in advance. Of the listed destinations are there any that do not need to be booked in advance for a cheaper fair. I played a bit on the National Rail site so from what I see so places seem not to make a difference.
I am looking at Bath with is much cheaper with advanced booking. My original plan was a day trip to Bath and a different day a trip to Cardiff. Now I am thinking it may make more sense to do Bath to Cardiff (sleep in Cardiff) then Cardiff back to London. This would be booked in advance. If it makes more sense happy to do them as two day trips.
York is also a thought but have not looked into that much yet.
Other places where I am interested are
Do I need advanced booking for these destinations. Brighton did not seem to save money if I booked in advanced but could be mistaken. Any special train pass that would allow me to save money on my trips.
What happens if I am booked and a train strike happens do I get a refund? I know they often set dates in advance but if I have booked what is the process.