Hi! It's, awesome you are planning a trip around beautiful Hungary, I can certainly provide some helpful tips.

Best Time to Visit:
The best time to visit Hungary is during their shoulder seasons of April-June and September-October. During this time, the weather is pleasant, the hotels are cheaper and the tourist crowds are not as packed.

Route and Accessibility:
Szentendre, Kecskemét, and Pécs are all accessible by train from Budapest, the capital of Hungary. Szentendre is just a short 40-minutes away by train, while Kecskemét will take approximately 1.5 hours. To reach Pécs, it generally requires a train journey of around 3 hours.

Accommodation and Booking:
Accommodation options are diverse in all these destinations with options including hotels, guesthouses, hostels, and private vacation rentals. It's advised to book well in advance during the peak season to ensure availability.

Clothing and Essentials:
Pack light with versatile clothing, preferably layers you can add or remove based on the weather. Don't forget to pack comfortable shoes for exploring the city, and necessary travel essentials like your ID, passport, medical supplies, travel adapter, and reusable water bottles.

Health and Safety:
Hungary is generally safe for travelers. But as always, monitor local news for any unusual events and keep emergency contact numbers handy. It's advisable to secure travel insurance for unforeseen circumstances.

Local Etiquette and Respect:
Hungarian culture appreciates politeness. It's best to learn a few simple phrases such as 'Thank You' (Köszönöm) and 'Excuse Me' (Elnézést) in Hungarian. Respect local traditions, especially in smaller towns or villages.