Certainly! Visiting these cities in Spain is always a good idea. Here are some travel tips to make your journey hassle-free and enjoyable:

Best Time to Visit:
The ideal time to visit these cities in Spain is during the months of March to May (spring season) and September to November (fall season). Avoid summer, especially August, as it can be very hot, and many places might be closed too.

Route and Accessibility:
Start your journey in Madrid and then continue towards Valencia, Barcelona, Granada, and end in Sevilla. Spain has an excellent rail network which will allow you to travel comfortably between these major cities.

Altitude and Acclimatization:
These cities are on a relatively low altitude, hence you won't have to worry about any acclimatization issues.

Accommodation and Booking:
Spain has a wide range of accommodations to suit every budget. Book your accommodations in advance, especially during peak tourist seasons. Be sure to consider the location of your accommodations in relation to the city center and the attractions you plan to visit.

Clothing and Essentials:
Pack lightweight, breathable clothes if you're visiting in the spring or fall, but also a jacket or two for cooler evenings. During the summer pack sunblock, hat and sunglasses. Remember comfortable shoes for walking and sightseeing.

Health and Safety:
Spain is generally a safe country. For health, if you have a pre-existing medical condition, make sure you bring all your necessary medications. Tap water is safe to drink, but keep yourself hydrated if you're visiting in the hot summer months.

Local Etiquette and Respect:
Spaniards are relaxed and leisurely, so don't rush or be impatient. Respect their local culture and traditions, especially during festivals. When visiting churches or religious sites, dress modestly. Try to learn a few basic Spanish phrases, it will be appreciated.