Hello! That sounds like an exciting trip to Greece. Here are some tips to help ensure you have a great time visiting Thessaloniki, Volos, and Ioannina.

Best Time to Visit:
The best time to visit these Greek cities is during spring (April to June) and fall (September to November) when the weather is mild and pleasant. This is also when they are the least crowded.

Route and Accessibility:
You can reach Thessaloniki via the Thessaloniki International Airport. From there, you can take a train or bus to Volos and Ioannina. Greek public transportation is quite reliable, and booking your tickets in advance is advised.

Accommodation and Booking:
All these cities offer a range of accommodations to suit different budgets. Booking online in advance is recommended, especially during peak seasons to secure good deals. Check out platforms like Booking.com and Airbnb for options.

Clothing and Essentials:
Pack lightweight clothing for summer months, and warmer clothes for the cooler months. Don't forget a good pair of walking shoes as these cities have beautiful sights that are best explored on foot. Also, carry a hat, sunscreen, and reusable water bottle for daytime explorations.

Health and Safety:
Greece is generally safe, but it's always wise to stay alert to your surroundings. Most visitors do not face any health issues. It's advisable to have travel insurance that includes health coverage. Also, pack an emergency medical kit with the basics.

Local Etiquette and Respect:
The locals in Greece appreciate it when visitors show respect for their culture and traditions. It's customary to say 'Yassas' (Hello) when entering shops. Tipping about 5-10% is appreciated in restaurants.