Absolutely, travelling to these locations in Vietnam is an exciting adventure. Here are some travel tips to make your journey enjoyable:

Best Time to Visit:
The complexity of Vietnam's weather from north to south makes it difficult to identify an ideal time that suits everyone. However, generally, the most recommended times to visit are October-November and April-June.

Route and Accessibility:
Fly into Hanoi, the capital city of Vietnam, then you can take the train or bus to Ninh Bình, which is about two hours south of Hanoi. Then you can take a train to Huế, after which you can easily reach Hoi An by car, bus, or motorbike ride. Remember, train travel is a great way to see the country and to meet locals.

Altitude and Acclimatization:
These places are near sea level, so altitude is not an issue. However, do be cautious of the heat and humidity.

Accommodation and Booking:
Both hotel and hostel accommodations are available in all these cities. It is advisable to book in advance, particularly if you are travelling during peak season.

Clothing and Essentials:
Carry lightweight clothes suitable for tropical climates. Don't forget to pack swimwear, sunblock, bug repellent, a lightweight rain jacket (it can often shower unexpectedly), and comfortable shoes for exploring.

Health and Safety:
Ensure that you are up-to-date on routine vaccines needed for travel. Carry a good mosquito repellent to prevent mosquito-borne diseases. Always drink bottled water and do not eat food that has been left uncovered for long periods of time.

Local Etiquette and Respect:
Vietnamese people are very polite, friendly and will appreciate it if you adhere to their customs. When visiting temples or pagodas, dress modestly and avoid wearing shorts or tank tops. Always ask permission before taking photos of local people.