Spain from Morocco

First, I would explore the possibility of flights from Marrakech to Spain. There may be something that will work for you. The ferry business will be a long slog by the time you get yourself from Marrakech to a Moroccan port and then from a Spanish port to a place you actually want to see. Try skyscanner.com for flight schedules. I know service is spotty now just about everywhere, but in normal times Vueling and Ryanair fly from Marrakech to Seville.

You can easily spend all your available time--and much more--in Andalucia. I agree that it makes sense to focus your itinerary there. Do check the actual, day-by-day, historical weather data on timeanddate.com. I have never been to Andalucia earlier than early April and have not researched what sort of weather you are likely to encounter. I had a short period of unpleasantly chilly, wet weather in Ubeda, and Granada (at modest altitude) will likely not be as warm as Seville.

I used only public transportation. You will need to use some buses in addition to trains if you want to go beyond Cordoba-Seville-Jerez-Cadiz-Ronda-Algeciras-Granada. I found the Spanish buses comfortable. You can manage without a car, I believe, but there's the caveat that I was dealing with springtime, rather than winter, bus schedules. I don't know whether you'll find less service to the smallest places at the time you are planning to travel.

There are usually one-day bus tours to Ronda and one or two additional white towns/villages, but again I'm not sure what will be running so early in the year. I'll list below the side-trips I was able to make in April 2019 by public transportation. What some people do is rent a car for one trip from west to east (or vice versa), hitting a few of the little places along the way. There's no problem traveling between Seville and Granada directly (it's a well-worn tourist path), and Ronda has a train station, but getting to places like Arcos de la Frontera, Grazalema and Zahara de la Sierra does require careful logistics even in peak tourist season. Trying to see the white towns smaller than Ronda without a car may take longer than you want to spend on that activity; I had a month in Andalucia.

These were my side-trips (only one destination per day)

From Ubeda: Baeza and Jaen (this area not on the fast rail lines)
From Cadiz: Vejer de la Frontera (I believe also accessible from Cadiz)
From Seville: Carmona and Arcos de la Frontera (latter used to be accessible from Cadiz as well)
From Ronda: Grazalema (in 2019 one could not day-trip to Zahara due to the bus schedule)
From Granada: Priego de Cordoba; also the Apujarras foothills, but that might not be smart early in the year

Early historic sites are definitely not my thing; I trust that others will help you out there. I will mention that Medina Azahara, outside Cordoba, was highly recommended by one of the other posters here but I just didn't find time for it. It sounds as if it's a place you should consider.

Oh absolutely FLY from Marrakech to Seville - and definitely visit Cordoba.

I would also stay south, as you are thinking. All the rest of Spain is there for later, but for a two-week visit, focus this trip on Andalusia.

Do check the actual, day-by-day, historical weather data on timeanddate.com. I have never been to Andalucia earlier than early April and have not researched what sort of weather you are likely to encounter.

I've spent time on the coast in February and the climate was pleasant. Sunny days which were warm enough for shorts and T-Shirt (for a Brit, the locals dressed in winter clothing!) and no rain, the wettest period I've been is April which is consistent with historical data.

Don't waste time travelling by ferry, fly from Marrakech. It'll be cheaper and more convenient.

The Rome2Rio website may be a useful first stop (but only the first stop) as you are exploring your transportation options. It's usually accurate about whether there's rail service and/or bus service connecting two points of interest, and it generally identifies transfer points (if required) correctly. Beyond that, it can be very inaccurate. Do not trust the fares, travel times or frequencies it displays. Instead, keep clicking down through the website until you find the name of the bus company serving the route you're interested in. Go to its website (Rome2Rio usually provides a link) to get accurate schedule information.

Use Renfe.com for rail schedules. I imagine you already know that rail tickets between major cities on the AVEs can be much less expensive if purchased well ahead of time. In these trying times, however, it's important to consider the risk of buying non-refundable tickets. Check the website for the rules on Basico and Elige tickets.

Both trains and long-distance buses sometimes sell out, so it's not a bad plan to go ahead and buy your tickets once you're sure of your preferred travel date and time.

The Rome2Rio website may be a useful first stop (but only the first stop) as you are exploring your transportation options. It's usually accurate about whether there's rail service and/or bus service connecting two points of interest, and it generally identifies transfer points (if required) correctly. Beyond that, it can be very inaccurate. Do not trust the fares, travel times or frequencies it displays. Instead, keep clicking down through the website until you find the name of the bus company serving the route you're interested in. Go to its website (Rome2Rio usually provides a link) to get accurate schedule information.

Use Renfe.com for rail schedules. I imagine you already know that rail tickets between major cities on the AVEs can be much less expensive if purchased well ahead of time. In these trying times, however, it's important to consider the risk of buying non-refundable tickets. Check the website for the rules on Basico and Elige tickets.

Both trains and long-distance buses sometimes sell out, so it's not a bad plan to go ahead and buy your tickets once you're sure of your preferred travel date and time. If you somehow end up in Madrid, do not under any circumstances plan to buy a long-distance rail ticket at a staffed counter at Atocha Station. It will take an infuriating amount of time; I waited in line for about 3 hours. There are vending machines that may (or may not) work with US credit cards. There may be machines that take currency as well.

Just make sure you keep an eye on the covidrelated travel rules. A lot can happen until March, but at the moment non-EU citizens are not allowed to enter Spain from Morocco.