So my siblings and I have gifted my mum and stepdad (currently living in Toronto) a trip to Spain in April. Perhaps foolishly, we gave them the airline tickets as a surprise but didn't want to plan a whole detailed itinerary until we could get their input.

Now that I'm trying to help them map out their trip, I'm getting a bit bogged down in the constraints. They're in their 70s, my mum is a fairly active walker and speaks rudimentary Spanish, my stepdad is probably not up for too much walking. They are excited but somewhat cautious about this trip (neither has done any travelling in continental Europe in a few decades, though she spent a fair amount of time in Spain in the 1970s), they hate flying and airports, they're not keen on spending more than about 5 hours at a stretch sitting in a train, renting a car is out of the question, they won't want a lot of consecutive days of getting from one place to another (i.e. few or no 1-night stops). They're flying into Barcelona on Sunday 13 April and back from Madrid on Tuesday 22 April. It turns out the place in Spain my mum most wants to visit is Seville. So the overall outline is probably going to be Barcelona - Seville - Madrid.

Where I'm specifically stuck is trying to think of somewhere they could spend a day or two between Barcelona and Seville that would break up the journey between the two into slightly more manageable stages (the shortest direct Barcelona-Seville train option seems to be about 6 hours via Madrid).

• My mum has suggested Valencia, which logistically makes a certain amount of sense (it's 3 hours by train from Barcelona, and there is one daily AVE from Valencia to Seville that takes 4h20m). What I'm not sure of is whether Valencia is an interesting enough place to be worth spending a full day or two there? I searched the term "Valencia" in this forum and literally every reference I could find to its merits as a destination is along the lines of "don't bother". This fits with the impression I've gleaned elsewhere - i.e., that it's a big city that is probably pleasant enough to live in, but if you had to visit only 3-4 places in Spain there aren't a lot of obvious reasons why Valencia would make the cut.
• There is, of course, Madrid itself, but I have a certain aesthetic reluctance to having the itinerary be Barcelona - Madrid - Seville - Madrid; still, it might be the most practical option.
• The ideal place would be somewhere relatively small and picturesque, preferably but not necessarily on the coast. But I'm struggling to come up with anywhere like that that can be fitted neatly into a train itinerary between Barcelona and Seville.

Posting this here just on the off-chance that anybody more familiar with Spain than me (only spent a few days in Barcelona once) has any brilliant suggestions that they would be kind enough to share, or if there are any Valencia enthusiasts who can make a case for it. (As it is, I'm inclined to advocate for either the stop in Madrid, or just doing the Barcelona-Madrid-Seville AVE in one fell swoop and keeping the actual city time in Madrid at the end.)