General Train Advice

There's no real advantage in buying tickets in advance except for cost, and for not having to worry about the time it takes to buy tickets if you are delayed on your way to the station.

British trains will not "sell out", as unlike in a few other countries they never have compulsory seat reservations. If they are very crowded and you don't have a seat reservation you may find yourself standing for all or part of the trip.

Since daytime trains in Britain don't require reservations, they can't sell out. (Overnight trains do require a sleeper booking.) The cost savings is the only reason to book ahead, and it can be significant, but is greater when booking up two months ahead, as the number of discounted seats are limited. There's still time to buy a BritRail Pass for home delivery before you go. That's fully flexible, allowing you to hop on any daytime train without a reservation, or to make a free seat reservation up to a day before at a station. There's no 5-day version, but you can consider 4 travel days within a month at $314 per adult or perhaps 8 consecutive days at $355, if you have a few days in London at one end or the other of your trip. See more about both tickets and passes at https://www.ricksteves.com/travel-tips/transportation/trains/britain-rail-passes.

You are too late to get the really good Advance fares. They sell out 10-12 weeks ahead. So looking today at tickets from London to York on Sept. 2, for example, you will see tickets labeled "Advance" for £62.50. This is about a third off the full off-peak fare of £98.70, but not nearly as good as the discounts offered on Advance fares bought way ahead. Those are as low as £19. We scored two of those on our last trip.

You might look into a " Two Together" Railcard which gives you 30% off a pair of tickets for two traveling together. The discount is in addition to whatever discount you get for early purchase, but also applies to tix bought at the last minute at the station.

Some routes offer flexible "anytime" tickets but many do not. Make sure you understand the rules for the particular fare you purchase.

Paul - Not rude at all and I do know that! I was concentrating so hard on how to ask the question that I wasn't paying attention....

Thank you all for the prompt and insightful responses. One follow up - if I do purchase an advance ticket, but then need to change plans - what's the penalty? Do you just pay the difference or have to rebook completely. Many thanks again!

If you want to change your Advance ticket

"The difference between the price paid and cost of the next suitable fare for your journey is payable, plus an administration fee of up to £10 per person."

http://www.nationalrail.co.uk/times_fares/ticket_types/46546.aspx

Some journeys do not require Advance tickets - if you tell us your routes we could say if you'd be better off buying Advance tickets.

Also note that you can break your journey as often as you like with the return part of most anytime/off-peak return ticket within a month. So if doing a round trip, go to the farthest point directly and work your way back. Details of your itinerary would be useful.

It isn't so black and white.

There are also various off peak tickets, singles and day and period return.

If you share the journeys you are making, and what day of the week and approximate time of day, we can give you much more help.

Nigel - thanks for the continued help. Here's what we need:
Wednesday 8/31 AM - Manchester airport to Lincoln - not planning to purchase advance in case flight is delayed.
Thursday 9/1 - afternoon - Lincoln to York
Saturday 9/3 - most likely morning - York to Edinburgh
Monday 9/5 - morning - Edinburgh to Inverness
Saturday 9/10 - midday to afternoon - Dunbarton to Manchester Airport
I am tired just looking at this! Not one of our better efforts at trip planning, but it is set at this point. Again, thanks all for any suggestions.

Lincoln to York - Advance from £7.50; walk up £37.10

York to Edinburgh - Advance from £27.50; walk up £86

Edinburgh to Inverness - Advance from £16.20; walk up £42

Dumbarton to Manchester Airport - Advance from £12; walk up £78

just book them all through this website ASAP

https://www.virgintrainseastcoast.com/

Thanks all for the advice!