You have already done some worrying about this so you might as well still go, but make things easy for yourself. So if you can afford to , go for 3 days , so that you travel on one day, stay b/b and you have managed the journey there which is enough for that day. Then you should be able to find out the route to the concert and probably best way there etc from your b/b or if not go to their local library or ask for info re buses and taxis to the concert. Then the next day you have the concert, and on the third day you will be going home having had a rest at the b/b after the concert.
So if you are going by rail I would actually go to the station and speak to a real human who knows your station! and the best journey for you to go. e.g there may be an earlier train, but a little later train may be more direct , or there will be less changes for you to make. If you have booked your seat, you know that you have your place, and you can ask for passenger assistance When that is booked, the assistant will be given your seat information and be waiting for you at that carriage. If you do not see them actually there when you get off, just ask any member of staff or another passenger to tell them you are waiting for booked assistance . Just stand there and they will appear.
I am older than you and have a bad back so have now had to use this service, which has worked quite well I found, although as you say , you are not totally in control .So I have booked this early ,and then the day before travelling I go to the station - but no doubt you could ring up - and confirm that they have booked my assistance and that there is no major hold ups or problems expected for the next day. I go in plenty of time to allow for any hold ups getting to the platform and have a case with wheels. This way I feel in as much control as I am able.
I usually drive and of course am then in total control ,and can choose my times and the way I will go and can change my plans exactly as I wish, so that is my preferred mode of travel, but very long distances I enjoy using the train once I have got on. So using the above methods keeps the anxiety down to a reasonable level.
The main thing now is to think how much you want to see this concert? if they are important to you, I do urge you to go, and allow for the fact that you might have to make more arrangements or stay another night or whatever. However expensive it is, and whatever the uncertainty of the journey , you will ALWAYS regret it if you dont go. You may regret something about the journey or whatever if you go but you have lived this length of time and chosen your way through your life full ,as everyones life is ,of what ifs, some regrets , but if you also look back , so many things that you might not be able to do any longer but were so pleased that you did it when you were able to.
I have sung all my life including being a professional singer in Portugal for 2 years, so music of all sorts matters a lot to me.
More than 40 years ago when I was living in the Nottingham area ,my husband was down in London on business ,and 2 friends and I used to go to concerts together . They had just opened the box office for Glyndebourne in London, for of course at the time , very expensive tickets. We all three worked and I said what do we work for.? So I got my husband to go and queue up and I also bought a ticket for my mother who also was a musician, for her birthday.
He queued and got the tickets, and when the time arrived, we did it in style. You can either have a picnic or eat inside, but the picnic is the thing if it doesnt rain, when you would have to sit in your car to eat it! We took the chance, picked up my mother on the way, had our own lovely picnic that we had made ourselves and bottle of wine etc. Took our lovely dresses packed carefully and drove in trousers etc. We found some woods where we were able to change into our outfits and the weather was beautiful and we had a marvellous evening listening to Mozart's Cosi Fan Tutti. We sat out in the interval in the beautiful gardens with the bats flitting overhead and with people all in their groups. - Think a sort of Downton Abbey kind of occasion!
My mother and both my friends have since died, but I have such a wonderful memory of the whole occasion and is was a special day in my and our lives. I have never regretted a single minute of it and when I hear the music from this opera I am transported back to that day. I have long ago forgotten the exact cost of the concert, dresses, food and travel and just remember it as a very special and wonderful day of my life that I have never and will never regret.
I think we worry more as we get older, not just because of our annoying infirmities, but our lifelong experience tells us things can go wrong . But you know, as they say, you could be run over by a bus just outside your house, so at least take the risks for enjoying yourself. Life has been tough and miserable these last few years and we have not had a good summer etc, so take the plunge and GO FOR IT Even if they dont turn out to be as good as you remembered them, or whatever, you might come back saying you wont bother again but stay in charge of your own life and enjoy what you can. Life is for living, Remember there are no pockets in shrouds!! Do let me know if you get there. Best of luck