Sure, these are some of the top destinations in Thailand! Here are some travel tips for your visit to Bangkok, Chiang Mai, and Phuket:

Best Time to Visit:
The ideal time to visit Thailand is during the cooler, dry season between November and early April.

Route and Accessibility:
Bangkok has an international airport and serves as the main gateway for international travelers. From Bangkok, there are regular domestic flights to Chiang Mai and Phuket available. Also, train, bus, and boat services operate between these locations.

Altitude and Acclimatization:
Bangkok, Chiang Mai, and Phuket are located at a lower altitude so you won't need acclimatization. However, it can get incredibly hot so stay hydrated and use sun protection.

Accommodation and Booking:
There is a wide range of accommodations available, from budget guesthouses to luxury resorts. Book in advance, especially during peak travel periods.

Clothing and Essentials:
Thailand is a tropical country so lightweight clothing is suitable. But remember modest dress for temples (especially in Chiang Mai). Definitely pack a swimsuit for Phuket's beaches, sunscreen, hat and comfortable footwear for city tours.

Health and Safety:
Use mosquito repellent and sunscreen. Stay hydrated and be careful about street food if you have a sensitive stomach.

Local Etiquette and Respect:
Thai people are very respectful and it's important to reciprocate that respect. Don't touch anyone on the head (considered sacred), always remove your shoes before entering someone's home or a temple, and never disrespect the Thai Royal family.

Thailand has some of the most stringent lese majeste laws in the world, and anything interpreted as disrespect for the monarchy is punishable by long prison sentences.