Sure, these cities in Japan are an excellent choice for travelling. Here are some travel tips for your visit to Tokyo, Sendai, Yamagata, and Akita:

Best Time to Visit:
The ideal time to visit is during the Spring (March to May) to witness the beautiful cherry blossoms, and Autumn (September to November) when the trees are vibrant with fall colors. Also, the temperatures during these seasons are very mild and comfortable.

Route and Accessibility:
Tokyo is well connected by air with major international cities. To travel within Japan, Shinkansen (bullet train) and domestic flights are quite convenient and efficient.

Altitude and Acclimatization:
The cities of Tokyo, Sendai, Yamagata, and Akita are all at low altitudes. So, you don't need to worry much about altitude sickness.

Accommodation and Booking:
Japan offers a wide range of accommodations like luxury hotels, traditional Ryokans, guesthouses, and Capsule hotels. Booking’s should be done in advance particularly if you are visiting during peak season.

Clothing and Essentials:
During spring and autumn, pack light to medium-weight clothing. For winter (December to February) pack warm clothes as it can get quite cold especially in Northern part like Akita. Don't forget your travel adapter for your electronic devices, as Japan uses Type-A and Type-B plugs.

Health and Safety:
Japan is generally a safe country with a low crime rate. But still, maintain standard precautions. It's recommended to have travel insurance. If you have any specific medications, carry them in their original packaging along with a copy of the prescription.

Local Etiquette and Respect:
In Japan, it is customary to bow while greeting. Tip is not practiced in Japan, as it is considered impolite so avoid that. Use Suica or Pasmo cards for payments in trains and buses.

Using phrases like "Arigato" (Thank you), "Sumimasen" (Excuse me) shows respect and appreciation toward their culture. Avoid talking loudly in public places as it's considered rude.

Lastly, always carry cash as many places do not accept credit cards and enjoy your trip to Japan!