Sure! East Africa, particularly Somalia, is certainly a unique destination offering a blend of fascinating history and vibrant culture. Please find some travel tips for your journey below:

Best Time to Visit:
The best climate conditions in Somalia are often from December to March, when the weather is cooler and more pleasant. The temperatures can rise significantly from April to November, which might be uncomfortable for some tourists.

Route and Accessibility:
Mogadishu, Marka, and Kismayo are all major cities of Somalia. You can fly into the Mogadishu international airport and then drive or fly to Marka and Kismayo. The road conditions in Somalia can be challenging, so consider traveling by air if short on time or seeking comfort.

Altitude and Acclimatization:
These cities are located at near-sea level elevations, so complaints related to high altitude are unlikely. However, acclimatizing to the hot climate is essential. Drink plenty of water and avoid long exposure periods to the sun.

Accommodation and Booking:
Hospitality industry in Somalia is developing, thus plenty of reasonable accommodations are available in all the three cities. Make sure to book your stay in advance, especially during peak travel seasons.

Clothing and Essentials:
Light, breathable cotton clothing is ideal. Pack a hat, sunglasses, and ample sunscreen as the sun can be quite intense. Do also pack a few conservative outfits respecting the local culture, especially when visiting religious sites.

Health and Safety:
Somalia has been dealing with conflict and instability for years. Ensure your safety by always staying in well-traveled areas, choosing a reliable local guide, and keeping abreast of the current political situation.

Local Etiquette and Respect:
Somalis are predominantly Muslim, so dress modestly and respect the local customs and traditions. Avoid photographing people without their permission, and always ask before entering religious sites.

Remember, travel insurance is a must for any international travel, it's even more important when traveling to regions with instability. Travel with your wits about you, be cautious and make the most of your adventure.