train tickets - purchase in advance vs. wait for flexibility

Tickets bought well in advance usually about 3 months out will be much less expensive. You could search your trip online tomorrow and see the price and search 3 months out to see the difference. We trained London to Edinburgh in November and buying tickets in advance they were about 27 GBP one way. On the day of they were like 150 GBP. Seat61.com is a great resource to learn about buying tickets. If cost isn't a concern then pay for flexibility. Probably won't sell out unless it's a particularly busy travel day.

You may also want to explore if a "two together rail card" would be a good value for you.

Note that with the 2 Together Railcard (£30), you are not allowed to travel before 9.30am on weekdays - unless it is a public holiday.
Even buying a ticket the day before can save money, but, as has already been said, pre-booking these longer journeys for specific trains around 11 weeks ahead can save big bucks. I find www.nationalrail.co.uk to be the best site for finding the schedules and fares - when you click to book - it sends you through to the train company on which most of your trip will be made. However, you can book any British train journey at www.crosscountrytrains.co.uk - who do not charge the £10 fee for changing arrangements at a later date - but you will be hot with any increase in the price.https://www.twotogether-railcard.co.uk

And make sure you're not travelling on a bank holiday! Did that once by mistake; luckily had seat reservations, otherwise we would have stood from Edinburgh to York.

There is a 3rd option for train tickets: off-peak. Cheaper than full price; more expensive that advance. Have to travel starting about 9:15/9:30. Are flexible as to which trains used. Can be bought up to the day before.

Denise, only you can judge the value of flexibility versus price to yourself. If your hotel dates are fixed, seems like you'd want to fix your rail as well. You'd be paying a big price for a couple of hours of time. How to research? Spend time on the National Rail site, pricing tickets, and see the difference.

The other advantage to buying ahead of time (online) is getting the seat reservation at the same time. Even if trains don't sell out, they can be crowded.

The place in Rick's guidebooks where these transportation issues are addressed is in the "Practicalities" chapter at the back (before the Appendix). On this site, you can find some similar info on our BritRail page.

There can be a bit of value in non-Advance tickets that doesn't get a lot of publicity - the fact that it is possible to break the journey as much as you like.

For off-peak returns, in general the outward portion is valid for a day and the return for a calendar month.

For anytime returns the outward portion is valid for five days and the return for a calendar month.

So for the sake of argument you could on a return ticket from London to Edinburgh stop over outwards in the Midlands and the Lake District, and return stopping off at Newcastle, Durham, York, Peterborough and Cambridge.

Of course separate tickets for each leg might still work out cheaper.

Off-Peak and Super Off-Peak are both turn-up and go tickets with the restrictions on time of use, they usually don't need to be purchased the day before.

Advance (with the capital A) are the big money savers and must be purchased the day before, or for the best deals as stated above, much sooner. There is a movement afoot to move the deadline closer to the departure time but that won't be for the deep discounts available for when they are released 12 weeks out.

Anytimes are the most expensive, valid as it says at anytime.

Don't miss Marco's advice about getting extra value out of a non-Advance ticket.

Thank you all so much. I had no idea the cost difference would be so significant, that's exactly what I needed to know. I don't need the flexibility, just thought I would keep it if there wasn't much of a trade-off. I also appreciate the explanation about Advance vs. Off Peak, that's helpful! I'm going to check out those advantages and then figure out by 12 weeks in advance. Thanks again all!