Absolutely! Thessaloníki, Volos, and Ioánnina are some of the most beautiful and vibrant cities of Greece. Here are some travel tips for a smooth and enjoyable trip:

Best Time to Visit:
The best time to visit these cities is spring (April to June) or fall (September to November) when the weather is pleasant and not too hot. Summer (July-August) can get quite hot, particularly in Thessaloniki.

Route and Accessibility:
All these cities are well connected by trains and buses from Athens. You can fly into Athens and then take a train or bus to these cities. For travel within the cities, public transport like buses, trams, and taxis are easily available.

Altitude and Acclimatization:
These cities are at sea level, so altitude won't be a concern. However, take some time to acclimatize to the weather and time difference.

Accommodation and Booking:
There are various accommodation options ranging from luxury hotels to budget hostels and vacation rentals. It is advised to book your accommodation in advance to get the best deals and assure availability, especially during peak tourist season.

Clothing and Essentials:
Pack clothes as per the season of your visit. Always carry a good sunblock, hat, and sunglasses for protection against the Mediterranean sun. Comfortable shoes are a must as you'll likely do a lot of walking exploring these beautiful cities.

Health and Safety:
Greece is generally safe, but take standard precautions to protect your belongings. Stay hydrated and carry any necessary medications you might need.

Local Etiquette and Respect:
Greek people hold their traditions and customs in high regard. Respect local customs, especially when visiting religious places. It’s also customary to tip for services in Greece.
Remember, a good amount of Greeks speak English but learning a few Greek phrases like ‘hello’ (Γεια σου) and ‘thank you’ (Ευχαριστώ) will be appreciated by locals.