Sure, both Dumaguete and Siquijor in the Philippines are charming destinations with a lot to explore. Here are some travel tips for your trip:

Best Time to Visit:
The best time to visit Dumaguete and Siquijor is during the dry season, usually from December to May. The weather will be suitable for outdoor adventures and beach hopping.

Route and Accessibility:
If you're coming from Manila or Cebu, you can fly directly to Dumaguete airport. From there, it will take you about an hour ferry ride to reach Siquijor. Ensure to check the ferry schedules in advance.

Altitude and Acclimatization:
Both Dumaguete and Siquijor are at sea level, so there's no need to worry about altitude sickness. However, do allow yourself a day or two to acclimatize after your flight, especially if you're coming from a long distance.

Accommodation and Booking:
Both destinations have a wide range of accommodation options, from budget to luxury. I suggest booking your accommodation in advance, especially if you're traveling during peak season (April-May).

Clothing and Essentials:
Pack lightweight clothes, swimwear, and protective gear such as sun hats, sunglasses, and sunscreen. Bring a reusable water bottle to stay hydrated.

Health and Safety:
Stay updated on weather forecasts in case of sudden changes, and always heed local advisories. Drink plenty of water and protect yourself from the sun. Since you might be exploring nature, it's also important to have basic first aid skills.

Local Etiquette and Respect:
Locals are very friendly and respectful, and it's important to return the same courtesy. Always ask for permissions before taking photos of locals or sacred sites. Furthermore, preservation of local ecosystems is vital, so practice responsible tourism.