I can't currently log into Scotrail, but I know they are working on the website. I can look at tickets and times. The last time I looked, there was no advantage to purchasing train tickets in advance. Then today when I looked at the website, I can see that the Glasgow to Fort William route has an Advance Single ticket. There are only two times a day this train runs, so I'd take the 12:22 train and I really don't need any flexibility on this ticket, so unless I'm not understanding something, I will go ahead and purchase.
I will be starting that day from Edinburgh, and the 10:15 train makes the most sense. It appears that the ticket is an anytime day ticket so I could purchase day of.
When I see split ticketing offered, can someone confirm that I am locked into the specific times? Also, what does "overtaken service" mean?
For my return to Edinburgh from Oban, there's an 8:56 and a 12:11. Both have a split ticket options, but I'm thinking that I'd have to use the exact times of the ticket? So, I'm thinking I will buy the 12:11 anytime single, and hopefully take the 8:56 train (the 8:56 anytime single is more expensive)
I checked all my other train journeys including Fort William to Mallaig and there doesn't seem to be any advance purchase ticket advantage.
Since I can't log into the website, hopefully when I go to purchase the advance single tickets, the transaction will go thru. Otherwise, I will use LNER or other UK train sites.
Thank you to everyone that is helping me with this trip. Incidentally, I found a taxi service that will take us from Fort William to Oban via Glencoe with Glencoe valley stops.