Absolutely, Spain is such a vibrant country to explore!

Best Time to Visit:
The best time to visit Barcelona, Valencia, and Alicante is late spring (April to June) and early fall (September and October), when the weather is pleasant and the cities are less crowded.

Route and Accessibility:
All three cities have international airports and they are well connected by Spain's train and bus network. You may choose to fly into one city and then take a train to the others.

Altitude and Acclimatization:
These cities are at sea level, so no need to worry about altitude sickness. Still, if you're flying in from far away, listen to your body and take it easy on the first day to adjust.

Accommodation and Booking:
Accommodation options in these three cities range from budget hostels to high-end hotels. It's recommended to book in advance particularly in peak season.

Clothing and Essentials:
Summers can get quite hot, so bring light, breathable clothing. Good walking shoes are a must, as these cities are best explored on foot. Also bring a hat, sunglasses, and sunblock as the Mediterranean sun can be intense.

Health and Safety:
As in any touristic city, keep an eye on your belongings, as pickpocketing can be a concern. It's also worth buying a travel insurance policy that covers medical emergencies.

Local Etiquette and Respect:
Spanish people eat their meals late by most standards: lunch is around 2 pm and dinner is rarely before 9 pm. Learn some basic phrases in Spanish; locals appreciate it. When visiting churches, dress modestly.