Absolutely, it sounds like you're in for a beautiful adventure through East Africa. I'm happy to provide some travel tips for your journey:

Best Time to Visit:
The ideal time to visit Nairobi, Arusha, Zanzibar and Dar Es Salaam is during the dry season, from late June to October, when wildlife viewing is at its best. December to March is another good period as it is a little cooler.

Route and Accessibility:
Your journey begins in Nairobi, which has international flight links to most parts of the world. From Nairobi, you can take a shuttle bus or a domestic flight to Arusha(5-6 hours by road or 1 hour by air). From Arusha, you can fly to Zanzibar(1.5 hours by air). Lastly, you will take a ferry or a flight to the final destination, Dar es Salaam(2-3 hours by ferry or 15 minutes by air).

Altitude and Acclimatization:
Nairobi and Arusha are at a high altitude compared to Zanzibar and Dar es Salaam. Make sure to acclimatize by taking things slow initially.

Accommodation and Booking:
Booking your accommodations in advance is advised. There are numerous options ranging from budget lodges to luxury hotels in all these cities.

Clothing and Essentials:
Pack lightweight, breathable clothing for the hot and humid coastal areas, and warmer clothes for the cooler Nairobi and Arusha. Don't forget your swimwear for the beautiful beaches of Zanzibar. Always have a hat, sunscreen and insect repellent on hand.

Health and Safety:
Ensure you are up-to-date on routine vaccines before your trip. Most travelers also get vaccines for Hepatitis A and Typhoid. Malaria is a risk in these areas so anti-malarial drugs are recommended. Always drink bottled water and be cautious with street food.

Local Etiquette and Respect:
Respect the local culture and traditions. In Zanzibar, which is largely Muslim, women should cover their shoulders and knees in public areas. Be aware that during Ramadan, eating, drinking, and smoking may be forbidden during daylight hours.