From 2 alternatives: Cardiff Castle and Kidwelly Castle we picked later (we can go to Cardiff Castle any time and we have been there before). We found trains, cross checked forecast, prepared something to eat and got off.

We needed to change trains in Llannelli. A slight glitch happened there - train was late. Every five minutes it was announced it is late bit longer. Finally, after 30 minutes they got enough of guts to tell us what I've already knew - service was cancelled (I have not travelled by train for the first time in UK. Last time it took about 2 hours of announcements "Train is approximatelly 10 minutes late" even everybody knew no train is going happen and in the best case bus will come to take us). So we found bus station and we could continue. Bus services cannot be compared with services of railways. Really kind and helpful driver, no little lies, just correct stuff. (OK, I am not really fair now, an attendant in train from Cardiff was really helpful and nice too.)

But overall - whole trip was very good and satisfying. We still had enough time to see what we wanted. And maybe we could be late bit more, because at the beginning heavy clouds were over Kidwelly and blue sky started only later.