Absolutely. Travelling to Japan will be a unique experience with its mix of traditional and modern attractions. Here are some travel tips for your trip:

Best Time to Visit:
Spring (March to May) and Autumn (September to November) are the best times to visit these cities as the weather is mild and the scenery is beautiful with cherry blossoms or autumn leaves.

Route and Accessibility:
Tokyo, Kyoto, Hiroshima, Kagoshima, and Fukuoka are well connected by the shinkansen (bullet train), local trains, and flights. Consider getting a Japan Rail Pass for unlimited rail travel.

Altitude and Acclimatization:
These cities are low altitude cities, so there should be little consideration for acclimatization.

Accommodation and Booking:
Japan has a variety of accommodation options from hotels, ryokans (traditional Japanese inns), to budget-friendly capsule hotels and hostels. Book early if you're traveling during peak season or during any major festivals.

Clothing and Essentials:
Pack according to the season. Summers can be hot and humid, while winters can be varyingly cold. If you're visiting in the rainy season (June and July) bring a good umbrella.
Comfortable shoes are a must for all the walking you'll be doing in these cities.

Health and Safety:
Generally, Japan is a safe country. Still, keep travel insurance in mind for unpredictable circumstances like missed flights or illness.
In terms of food, try to stick to places with hygienic conditions to avoid a bad stomach.

Local Etiquette and Respect:
Japanese are very conscious of manners. Avoid eating and drinking while walking in public spaces. Always bow slightly when greeting someone.
Remember to remove your shoes when entering someone's home or certain traditional restaurants / inns.
If you visit any shrines or temples, follow the specific etiquette there, like washing your hands and mouth at purification fountains and avoiding taking pictures of holy objects.
While in Hiroshima, visit the Peace Memorial Park with respect, considering its history.