Sure, Aden, Hadibu, and Qalansiyah are all unique places with different cultures and climates. Here are some travel tips:

Best Time to Visit:
The best time to visit Aden is during the winter months (December-February) when the temperatures are moderate. For Qalansiyah and Hadibu, the cooler months between September and March are recommended to avoid the intense heat of the summer months.

Route and Accessibility:
Traveling around Yemen is restricted due to security concerns. Check with local authorities and travel advisories before planning your trip.

Altitude and Acclimatization:
Aden sits at sea level but temperatures can rise significantly during the summer months. Hadibu and Qalansiyah are on Socotra Island and at a slightly higher altitude, but acclimatization is not usually an issue in either location.

Accommodation and Booking:
There are a wide range of accommodations available in Aden ranging from budget to luxury hotels. In Hadibu and Qalansiyah, you'll find a limited number of basic guesthouses, and camping is an option. Make sure to book ahead of time to secure a spot.

Clothing and Essentials:
Given the conservative nature of Yemen, it's advisable to dress modestly in all three locations. Also, don't forget to pack a hat, sunscreen and a good pair of walking shoes for exploring.

Health and Safety:
Check your health insurance to ensure coverage abroad. Be aware of food and water safety - it's advisable to drink bottled water only and avoid street food. And always be aware of your surroundings for personal safety.

Local Etiquette and Respect:
Respect local customs and codes of conduct. Always ask for permission before photographing locals.

Before traveling to these locations, please check for any travel advisories or restrictions as the safety situation in Yemen can be quite volatile. Always prioritize your safety and the wellbeing of the communities you are visiting.