Absolutely, I can provide some travel tips for your visit to these historic cities in Brazil.

Best Time to Visit:
The best time to visit these cities varies. For Recife and Olinda, the best time is between September and February when the weather remains warm and sunny. The Carnival in February is a major attraction. For Porto Seguro, the favorable time is during spring (September to November) when the weather is pleasant.

Route and Accessibility:
Direct international flights land at Recife's international airport while Porto Seguro also houses a well-connected airport. Olinda, being a UNESCO World Heritage Site, can be reached by bus or taxi from Recife, approximately 10 km away.

Altitude and Acclimatization:
These cities are at sea level, so there's no need to worry about altitude sickness.

Accommodation and Booking:
All three cities have plenty of lodging options, from luxury to budget accommodations. Booking is advised in peak season or during festivals such as the Carnival.

Clothing and Essentials:
Casual, comfortable clothing is suggested. Heavy clothing is not needed since these cities have a tropical climate. However, a waterproof jacket or windcheater might come handy if visiting in the rainy season. Also, sunscreen, hats, and sunglasses are recommended against the tropical sun.

Health and Safety:
Tap water is generally not safe to drink in these cities. Stick to bottled water. Dengue and Zika viruses have been issues in Brazil, so use mosquito repellents.

Local Etiquette and Respect:
Respect local customs and traditions, especially during festivals like the Carnival. Remember to ask permission before snapping pictures of locals, particularly at the Indigenous Reserves around Porto Seguro.