Absolutely! Here are some travel tips for your trip to Madrid, Valencia, Barcelona, and Zaragoza:

Best Time to Visit:
The seasons of Spring (April to June) and fall (September and October) offer moderate weather and fewer crowds in all these cities.

Route and Accessibility:
You can start your journey with Madrid, then head to Zaragoza, then to Barcelona, and lastly visit Valencia. The cities are well-connected by Spain's efficient train and bus system.

Altitude and Acclimatization:
These cities are located at low altitudes, so there's no need to worry about acclimatization.

Accommodation and Booking:
Booking your accommodation in advance is always a wise decision, especially in Barcelona and Madrid. There are various options - from high-end hotels to budget hostels and apartments.

Clothing and Essentials:
Light comfortable clothing should be sufficient during the day, but carry a few warm clothes for the evenings. Don't forget a good pair of walking shoes or comfortable sandals. Carry a water bottle, sunblock, hats, and sunglasses.

Health and Safety:
Spain is generally a safe country but beware of pickpockets in popular tourist areas, especially in Barcelona. Pack a basic first aid kit for minor health issues.

Local Etiquette and Respect:
Spanish people are generally warm and friendly. However, respect their siesta time (afternoon breaks) by avoiding loud noise. Most importantly, try to learn a few basic Spanish phrases, this will help you connect better with locals.

Enjoy your trip and make the most of Spain's rich heritage, delectable cuisine, and vibrant culture.