anyone know which of these train tickets are cheaper in advance?

In Reverse order-

York to GLA/EDI- Yes. Depending on how 'best' your fares, and how fast you want to get there, or if scenery and/or cost are more important than speed then there are a couple of ways to drive the cost down further;

Bath to York- YES. Via London is usually cheaper and no slower than via Bristol and Birmingham;

Oxford to Bath- NO;

London to Oxford- YES;

London (St Pancras HS1 Javelin or Victoria or Charing Cross conventional speed train) to Canterbury- YES (off peak) NO (peak with a few very early pre 0700 exceptions);

London to Cambridge- YES and NO
NO on the fast Great Northern trains from Kings Cross- £31.80 DR after 0930 or £46.40 before 0930
NO on Thameslink from St Pancras- slightly slower- same fares
YES on Greater Anglia from Liverpool Street- take twice as long as from Kings Cross but 2x Advance Singles £16 at any time, so you trade off speed for price.

Thanks so much for the helpful reply!
For London to Oxford, are you familiar with the oxford tube? it seems (?) like it's always the same price (13 pounds for an adult) and doesn't fluctuate. I've checked the train prices and they get much higher. Why wouldnt everyone just take the oxford tube? It takes longer since it's a bus?

The price, even two months in advance, of London to York is much more than i expected, 80 pounds.

Bath to York is also cheaper when i buy two separate tickets, Bath to London and London to York than if i buy them together which is weird. Usually it's the other way.

Yes, the Oxford Tube is always the same price. It is very well used, but if you book well ahead the train is £6 each way, reduced to £3.90 if you have a railcard

They are high spec double deck coaches, the longest ones in the UK. There should always be one waiting outside Victoria. And they are well used as well. There used to be a competing service as well but that stopped during Covid.

I like the Oxford Tube, but it takes you twice as long as the train- which I guess is the issue.

Not sure what day you are looking at for London Kings Cross to York, but 12 June- which is a typical day- mid morning is between £28.50 and £40.

Bath to York that day, a bit unusually, is cheaper as 2 tickets- £24 Bath to Paddington and as above Kings Cross to York.

Maybe there is a big event happening on your date of travel to push the York fares up.

i was looking at paddington to york since that's where the trains from Bath come from. Do you think I should do Bath to paddington, tube to kings cross, and then kings cross to york?

Ah, that's the issue. Yes Bath to Paddington, tube to King's Cross then Kings Cross to York on LNER.

Just pay your tube fare as you would do normally- £2.70.

You can book a ticket from Bath to Kings Cross if you wish to include your tube fare but that add on is £3- so you overpay by a huge 30 pence!!

But you may find it worthwhile to be "swindled" like that.

train stations in London only each serve specific parts of the country.

Bath as you have seen is served by trains operated by GWR, and they all go into and out of London Paddington station. Areas southeast of Bath are also served by SWR which only serves London from London Waterloo station.

The main stations form a sort of a circle around central London, and are linked together, or nearly linked together when including those south of the river (Waterloo and London Bridge) by the Circle Line underground line.

To get to Oxford by train you need either Paddington station (GWR) or Marylebone station (Chiltern Trains, somewhat slower now).

To get to Canterbury you need either Victoria station (Southeastern) or for the very fast high speed HS1 Javelin trains you need St Pancras International station.

To get to Cambridge you either need London Bridge, Farringdon, City Thameslink or St Pancras International (Thameslink), or Kings Cross (Great Northern - fastest), or Liverpool Street Station (Greater Anglia - slowest and often cheapest).

To get to York you need (from London, there are other more expensive and slower ways) Kings Cross station (LNER, fastest, most frequent, goes all the way up into Scotland, LUMO (skips York and continues to Scotland, less frequent, or Grand Central Rail (infrequent).

So you can see that you need the right station, and understand the advantages and disadvantages of each operator.

If you're travelling on 14th or 15th June the races are on at York and that will mean the city will be very busy.

thanks everyone for the info!
Nigel, your post was so informative, thanks so much

in general, for any of my planned trips is bus recommended or should i stick to trains?

The trains are best for these routes. As you have asked about the Oxford Tube that is a valid alternative if you wish, and National Express run plenty of buses from London to both Canterbury and Cambridge. They are slower but different scenery.
Cheaper than the train to Canterbury if you want to get going early before the morning cheap trains start. Then you could do bus out, and train back.
To Cambridge there is less benefit as the cheap trains from Liverpool Street are available even in the morning peak.

Advance tickets between Oxford & Bath Spa disappeared around the last timetable change when the connections were somewhat improved at Didcot Parkway, but maybe too as the the trains on both legs are getting more crowded. Although changing at Reading is often around the same journey time it costs more.

There is nothing wrong with the Oxford Tube in general & if you happened to be staying close by to one of its stops the time penalty is lessened.

i'm on the national rail site, and it seems like oxford to bath spa rail tickets are cheaper in advance? am i missing anything? I see some trains cost 22 pounds and some 37... Also, is there another way to travel?

In general is the train the recommended way?

Those are not advance tickets. They are Super Off Peak Tickets which you can buy ahead of time (IN advance) or equally two minutes before departure-
£22 is for trains where you change at Didcot Parkway, £37 where you change at Reading.

If you have an open mind and don't just want the fastest way there are 4 other ways to do the journey. Train is fastest.

The other routes are-
Train to Didcot Parkway, bus X2 or X32 to Oxford- combined frequency of 5 buses an hour £2 fare;
Train to Reading, bus X40 to Oxford every half hour. Fare £2. I like that route a lot, double deckers on the route, from right outside Reading Station.
National Express to Heathrow, the Airlink Bus to Oxford (the most expensive route)
National Express to London Victoria, then the Oxford Tube bus to Oxford (the longest route)

The top two routes are the sensible alternatives, which allow you to see different parts of the countryside than on the train.

Although of no use to you, from September, GWR are going to have some direct trains going from Bristol > Bath to Oxford. If you click the link, you will see a map off the route. It really is no big deal to take a train from Oxford, get off at Didcot and switch to another train to Bath. https://news.gwr.com/news/great-western-railway-planning-to-restore-direct-bristol-oxford-services

It is possible to go from Bath to Bristol and then direct train to York - thus avoiding London. However, the Cross Country Trains on this route can get very busy & prices are high - even by splitting the ticket at places where the train calls.

I take it that you are flying directly home from Scotland?

isn31c, thanks so much for explaining it to me

James, thanks for the info on the trains. After Scotland I am going to Ireland and then home. I still have to buy some Irish rail/bus tickets and some bus tickets in Scotland.