Sure! These cities are vibrant and full of exciting places to see and things to do. Here are some travel tips for your trip:

Best Time to Visit:
Bangkok:
The best time to visit is between November and February, as it's the cool and dry season.
Singapore:
You can visit Singapore any time of the year as its weather is fairly stable, with temperatures ranging from 24-31 degrees.
Kuala Lumpur:
Anytime between May to July or December to February during the dry season.

Route and Accessibility:
Many airlines operate direct flights to these cities from various parts of the world, which makes it accessible. Internal city transport is excellent, with efficient train, bus, and taxi systems.

Altitude and Acclimatization:
These cities are at sea level, so there's no need for any kind of acclimatization.

Accommodation and Booking:
There's a wide range of accommodations available - from luxury hotels to budget hostels. Booking in advance can secure better deals.

Clothing and Essentials:
Pack breathable, comfortable clothing due to the tropical climate. Sunscreen and hats are highly recommended. Don't forget to carry a universal power adapter.

Health and Safety:
Follow regular health and safety travel guidelines, like keeping your belongings safe, taking care of your health, and eating at clean and good places.
Ensure that your routine vaccinations are updated, and consider vaccines for diseases like Typhoid and Hepatitis A.

Local Etiquette and Respect:
Respect the local traditions and customs. Dress appropriately, particularly when visiting temples. Remove shoes when entering someone's home or places of worship.
In Singapore and Kuala Lumpur particularly, it is good to know that littering and chewing gum are taken very seriously and can result in a heavy fine.