I am planning to travel Vietnam from Hanoi to Ho Chi Minh City in this October (2019) with only one stopover at Hoi An due to time constraint. Without being able to speak the local language, would it be advisable/possible? I would like to see and experience the scenes from the bus/train. I know flying would be faster, but the cost is just about the same. It is my first trip to Vietnam.

Let me suggest that you may want to reconsider that stop in Hoi An. October is monsoon season in central VN, and you can expect 20 inches of rain or more in October. We ran into the same issue when we visited VN in November. We chose to skip central VN, as the flooding is often severe, with loss of life.

Given that, I'd suggest that you fly between Hanoi and HCMC. Lack of local language will not be an issue. English is widely spoken.

Normally I would recommend the train, with a stop in Hue instead of Hoi An, but not in the rainy season, as Kathie says.

I agree with the above. The train our the preferred method of travel in Vietnam and we have done the trip from Hanoi to Saigon and vv, several times. During October there is a possibility you will be paddling through the streets of Hoi An. You don’t say how much time to actually have in the country but if >7days, I would just stick with the two cities. 10 days and you could take a couple of nights side trip, maybe the Mekong delta in the south or Ninh Binh from Hanoi. Some photos and detail of our travels in the county which may help you choose on our blog @ https://accidentalnomads.com/category/vietnam/

Thank you all for very valuable weather information. 20 inches of rain in a month is a LOT! I will bypass (fly over) Hoi An this time and hope I will get another opportunity to visit the city in the future.

Sounds like a good plan. Enjoy your time in VN.

Agree with aboves - Oct/ Nov is not a good time to visit Central VN (Do it for another trip).
Train is safer than bus (Remember to avoid night bus)!

You can consider to skip central region of VN in Oct - Dec, since the heavy rainy season, and even it cause extreme flooding. About the means of transport, trains could be the best choice, but it takes about 31- 35 hours depends on different train label. Moreover, English is widely spoken in Vietnam so local language not a big deal.

Was in Da Nang a few September ago. Perfect weather during the day, with a long deluge every night during the early hours.

Then moved on by train to Hue for 5 nights. Got caught in a Tropical Depression for much of that time, and spent far too much time in a bar watching the great spectacle of how the locals just take these inclement weather patterns in their stride.

Spent the following week in Hoi An....perfect weather throughout.

Pay your money and take your chance.

If you travel from the North to the South, I would recommend the train is preferrable. Because it's safe and more experienced to sightsee. Of course, bus is suitable for short distance in the city. Don't worry about the language. The touristy attractions all have English speakers.
Noted, October is rainy month in Vietnam but the weather is cool and easing.
Hope you enjoy your trip in Vietnam!

Trains are always preferable (except the one Hanoi-Sapa, where the day express bus on a new superhighway i better). For long distnaces, take night trains.
October bad month for the Center and Saigon-Hanoi is a grueling 34-hour affair, so take the plane and enjoy the fantastic Halong bay and northern mountains

To do Hanoi-Sapa, the very best is the DIRECT very comfy express bus SapaExpress , 5 hours (including 30 mn refreshments stop) on new superhighway instead of grueling 10 hours train + bus Lao cai-Sapa

Not an option when I did it. Sounds like a significant improvement.