Of course, here are some travel tips for your upcoming visit:

Best Time to Visit:
The Philippines is beautiful to visit year-round but generally, the dry season (December to May) might be more suitable for travelling. In terms of tourist volume, the months of January, February, March are the peak for tourism in those areas.

Route and Accessibility:
The easiest way to reach these destinations would be by air. The Ninoy Aquino International Airport (MNL) in Manila is the nation's busiest and largest airport. From there, local airlines have regular flights to Naga, Legazpi, and Sorsogon. For Donsol, you will need to take a bus or van from Legazpi.

Altitude and Acclimatization:
You won't experience any significant altitude changes in these areas as these are located at low altitudes. Therefore, acclimatization would not be a concern.

Accommodation and Booking:
Always book your accommodations in advance for these places. From budget to luxury, you can find a wide variety of hotels.

Clothing and Essentials:
Pack breathable, comfortable, and light clothing. Casual attire is generally accepted everywhere but modesty is advised while visiting religious places. Don't forget to pack swimming gear for the beach areas in Sorsogon and Donsol. A raincoat or umbrella might come in handy as sudden rain showers are quite common in the Philippines.

Health and Safety:
Carry essential medicines, antiseptic lotion, insect repellent, and sunscreen. Always keep an eye on your belongings and beware of pickpockets in crowded areas. Make sure to stay hydrated.

Local Etiquette and Respect:
Filipinos are known for their hospitality. Always be polite and respect local traditions. English is commonly understood and spoken so communication shouldn't be an issue. Most Filipinos are Catholics, so dress appropriately, especially when visiting churches or religious events.

In Donsol, if you are planning to go whale shark watching (which is a big draw there), make sure to follow the guidelines given for a responsible and respectful interaction with these magnificent creatures.