Madrid/Seville for 8 days

Seville and Toledo are my favorite Spanish cities.

Your plans don't include Toledo, which is a HUGE mistake.

You have two days in Seville, which is not enough.

Forget you plan for Day 4, unless you stop in Cordoba (between Madrid and Seville).

I would book a flight on a one-way ticket from Madrid to Sevilla and see Madrid at the end of your stay.

Day 4 - since it’s only a day trip I’d stick with Córdoba since it’s closest, followed by Cádiz. To me, the others are too far to go as a day trip

Another vote for Cordoba. The Mezquita is jaw-dropping! The city is walkable and welcoming. And, the food is great.

Cadiz/Malaga/Marbella/Granada/Cordoba - one of these - Please suggest, really confused (not planning to stay)

Really depends on what you want to see. Cordoba is easy to get to, with the main site being the Mezquita, with the old town being somewhat interesting.

Cadiz would be my other choice, great old town, direct train, great food and some sights.

Malaga I enjoyed, but not worth the effort to get there from Seville for a day trip, Marbella even less worth it, unless you are into high end shopping and resort town vibe.

Granada is really a bit too far for me for a day trip from Seville.

Looks like lots of vote for cordoba. Should we then stop at Cordoba starting from Madrid first, stay one night, and then go to Seville the day after?

I'm totally non-productive on my arrival day (jetlag and sleep deprivation), so I'd try to get to one of my destinations on that otherwise-useless day. Cordoba would be ideal, because it's not terribly far from Madrid. Madrid-Cordoba-Seville-Madrid is much more efficiently done by train than by car. The train to Cordoba is a bit tricky since you can't be sure exactly what time you'll be ready to leave the airport in Madrid. You have two choices:

• Buy a ticket in advance, choosing an option that allows changes or refunds. Buying well ahead of time can save a substantial amount of money, but try to get the timing right, because I think if you have to change the ticket later, you'll have to pay the extra cost of a last-minute ticket.

• Wait until you arrive at the airport to buy the ticket, either online or at the airport train station. The problem with this technique (which we'd usually recommend without caveats) is that trains on the Madrid-Cordoba-Seville line sell out pretty often. That's aside from guaranteeing you'll pay a higher price if you buy on the day of travel.

What you definitely should not do is plan to buy any of your train tickets from the staffed counters at Madrid's Atocha Station. The lines there are unbelievably long. The ticket-vending machines are easy enough to use as long as you don't run into an issue with your credit card (always smart to travel with multiple cards), but since there's a train station right at the airport, there's no real reason to wait until you get downtown to buy tickets.