I’m sorry to hear about the mobility issues. Luckily, transit systems in Spain are really good (uber was helpful too). I still think that Rick Steves would provide a great backbone/foundation and then build on it based upon exercise tolerance. We started in Barcelona, took high speed train to Madrid, day trip to Toledo, trained to Seville. Rented car, drove to Tarifa, took ferry across to Morocco (worth it), drove to Gibraltar (we hiked it, but the tram to the top would be worth it). Drove to Granada (Alhambra was amazing), drove to Cordoba (cathedral was so unique (half mosque/half church), then drove to Madrid for exit flight. Mostly booked hotels through booking.com. One of the highlight trips for my family. Rick (Steves) was our guide.