Hello! That sounds like an exciting trip across Slovakia you're planning. Here are some tips to help you prepare.

Best Time to Visit:
The best time to visit these cities in Slovakia is typically between May and September. During this period, the weather is warmer and more suitable for exploring the outdoors and vineyards which Modra and Pezinok are known for.

Route and Accessibility:
Starting with Modra, you could get there from the capital, Bratislava, by bus or train. Moving to Pezinok, you can take a bus ride from Modra. To reach Stará Turá, you can opt for a bus or train journey from Pezinok and finally, to get to Nový Smokovec, you may take a train from Stará Turá. Public transport in Slovakia is reliable and schedules can be found online.

Accommodation and Booking:
There are a wide variety of accommodations available, from budget options to luxury stays. It's best to book in advance, especially during the peak summer season. Booking can be done online via multiple websites, including the hotels' own sites if applicable.

Clothing and Essentials:
For the warmer months, bring lightweight clothing, comfortable walking shoes, sun protection, and a rain jacket since showers can be common. For visits to Nový Smokovec or during colder months, pack warmer layers and good footwear for snowy conditions.

Health and Safety:
Overall, Slovakia is safe for travellers. However, it's always a good idea to have travel insurance in case of emergencies. Make sure you're up-to-date on routine vaccines too. Tap water is safe to drink in Slovakia.

Local Etiquette and Respect:
Respect local traditions and customs. Slovaks value polite behavior. Always greet with a 'Dobrý deň' (good day). Tipping is generally expected in restaurants, about 10% is standard.