I must confess that I don't really follow threads about rail passes for reasons that I will not go into;-)
However an American friend of mine is coming to the UK in September for a fortnight.

She has an appointment in Oxford, but also wants to visit London, York and Bath.
She doesn't want the hassle of booking in advance and having to travel by particular trains although she realises that this would probably be cheaper.
She is thinking of getting a four day BritRail England pass.
I assume that the pass is cheaper than just turning up at the station even at off-peak times but I honestly don't know.

Can the Man in Seat 61 help?

http://www.seat61.com/UKtravel.htm

"I honestly don't know"

The answer to you has to be the same as the answer to conventional tourists from overseas: we don't either. You or your chum have to do the numbers, based on the trains she's likely to take, but remembering to:

- ignore the deceitful Ready Reckoner on the BritRail site
- use www.nationalrail.co.uk to cost probable journeys (the likelihood is there's no advance booking benefit from Suffolk to London or Oxford anyway)
- factor in the costs and benefits of appropriate Railcards. If a Senior Railcard is appropriate, she'll get 33% off just about all fares (and not just offpeak ones), AND be able to get 33% off the daily capped Oyster rate in London if she gets the ticket office to link the two cards.
- remember that, if I understand this piece of arcania properly, her day returns qualify her for 2-for-1 access to many attractions, whereas a BriRail pass doesn't.

Only you and she, though, are in a position to know which of these issues apply and matter in her case.

Thanks Flanner.
I had a vague feeling that I'd heard about that ready reckoner

I have no idea whether I saved money or not, but I did find having the pass convenient. I changed plans alot, and caught earlier or later than anticipated trains and shuffled around my itinary quite a bit. It was useful just being able to hop on at will.

If she doesn't want the hassle of booking in advance (and getting the advance rate fares), she may be better off getting a Britrail pass, which runs around $300 + for 4 flexible days first class. She might be even much better off hiring a car, but the cheaper cars (that would save the most money) have manual transmission. Meaning, you have to know how to use it, and be able to switch hands -- that is, shift with the left hand, steer with the right. For some, like me, it's actually easier than driving a stick in England than the U.S. -- for others, like my husband, not.