Bus vs train travel

Can the three of you climb steep stairs when getting on a bus? Do you pack heavy? If so, bus travel is easier because you stow your luggage before getting on. Train travel tends to be more comfortable than taking the bus though.

For most of the places on your list a rental car would be a liability. A rental car is handy when visiting smaller towns and villages not well served by public transportation. None of the places you list fit that category.

I’ve never been asked my age when renting a car, anywhere. Since I always rent a vehicle I cannot comment on which (bus, train) is better or easier to use.

We prefer train over busses and driving - that does limit where we go but we’ve also been able to visit smaller towns via train.. You may consider looking into private drivers and day tours. Since you’re a group of three hiring a private driver maybe a nice way to have the benefits of driving with none of the hassle. Perhaps someone on this forum can suggest reliable operators. Your hotels may have suggestions as well.

Have a look at the cost of Hertz rental - they do not have upper age limits and price hikes.

TRAINS for sure

Arrive Barcelona > Valencia > Granada > Ronda > Cadiz > Seville > Toledo > Salamanca > San Sebastian > Pamplona > Madrid > fly home.

Three or four weeks plus travel point-point makes this aggressive for my former 20 year old self, let alone my 56 year old present self. That's a lot (to me) to see and do with a car let alone with trains or buses. By car, 3,000+ km and over 30 hours of driving assuming no traffic and easy parking. A Cannonball Run of Spain!

After managing the original itinerary, I would definitely choose train where possible (much more relaxing), but if you can swing a car, I'd definitely would think that would give you a lot more flexibility to get out and see the countryside and small towns (and stretch, stroll, get a break from the car).

Try the Hertz route like noted above, but also consider bringing a fourth with you - child, grandchild, niece, nephew, etc - to do the driving.

That seems like too many places in 3--4 weeks, but that's your choice. Re discounts: there is a senior Pass (Tarjeta Dorada) that you can purchase to get discounts on Renfe trains. The problem is that you have to purchase the card in Spain and it's probably cheaper to buy your tickets in advance online. It would also be awful to not have certain tickets available if you wait to purchase while in Spain. We traveled by train Barcelona to Seville, took a bus Seville to Granada (times and fare were better than train), trains to Cordoba and Madrid. We took a bus for a day trip to Segovia. The travel was super easy and comfortable. As someone else pointed out, a bus is sometimes easier because you just wheel your big suitcase to the bus. Trains are a bit more comfortable but I don't mind a bus for 3 hours.

If you really want to see the countryside, there are many day tours available so you don't have to drive.

There might be porters at bus and train stations that help for a tip? I didn't notice but maybe someone else can comment.