Sure, travelling to Mellieha, Bugibba, and Sliema in Malta can be a unique experience. Here are some travel tips:

Best Time to Visit:
The best time to visit Malta is between late April to June, and September to October, when the weather is warm but not uncomfortable, and the tourist crowds are smaller.

Route and Accessibility:
All three locations are well-served by Malta's public transportation system, with regular buses connecting them to the capital, Valletta, and other parts of the island. It is also relatively easy to hire a cab, rent a car, or even charter a boat to travel around.

Altitude and Acclimatization:
As Malta is an island nation, altitude isn't a significant factor. Acclimatization is not usually an issue.

Accommodation and Booking:
There's a range of accommodations available in these areas, from budget guesthouses to luxury resorts. It's advised to book ahead during peak seasons.

Clothing and Essentials:
Bring lightweight, breathable clothing, as well as a good SPF sunscreen, and a hat for the hot summer months. Don't forget a swimsuit for those fantastic Mediterranean beaches!

Health and Safety:
In general, Malta is safe for tourists but always be aware of your surroundings and take precautions to keep your belongings safe. Ensure you have suitable travel insurance for the duration of your stay. Tap water is safe to drink, but bottled water is recommended.

Local Etiquette and Respect:
Maltese people are generally friendly and respectful. Likewise, tourists should respect local customs and traditions. Dress modestly when visiting religious sites.