Sure, here are some tips for your trip to these wonderful places in Singapore:

Best Time to Visit:
The months of February to April, between the Summer and Winter, are considered the best time to visit Singapore. The weather during these months is quite enjoyable and suitable for outdoor activities.

Route and Accessibility:
These places are well connected with public transportation. The MRT (Mass Rapid Transit) system in Singapore is very efficient and can take you to Yio Chu Kang and Bukit Mandai Village effortlessly. For Kampong Bahru, buses and taxis are convenient modes of transport.

Altitude and Acclimatization:
These places aren't located at high altitudes, so you don't generally need to worry about acclimatization. However, do ensure to stay hydrated given Singapore's tropical weather.

Accommodation and Booking:
You can find a wide range of accommodations in Singapore, from luxury hotels to budget hostels. Booking in advance is advised to ensure you get the best deals and desired locations.

Clothing and Essentials:
Carry lightweight and breathable clothing due to Singapore's hot and humid weather. Don't forget your sunscreen, hats, sunglasses, and a refillable water bottle. Comfortable walking shoes are a must for exploring.

Health and Safety:
Singapore has high standards of hygiene and healthcare. Tap water is safe to drink. Do take care of your belongings when moving in crowded places.

Local Etiquette and Respect:
Singapore is a multicultural city with a mix of traditions and customs. Always show respect for local culture and customs. Besides, Singapore has strict laws, so be mindful of them - for example, littering and chewing gum publicly can lead to heavy fines.

Have a great trip!