Motorized or otherwise? Unmotorized seems to have largely gone the way of the water buffalo (as it also has in neighbouring Laos, and or course China). All this despite the relatively-high cost of fuel. Only the very poor or the (very occasional) recreational/sports cyclist though they are available for rent in the less-crowded touristy places such as Mekong delta, Hoi An and (never noticed any in HCMC or HaNoi).

Was there at the end of November- early December 2023 for work. It is very touristy in the old quarter and the lake, had to go there twice for work dinners etc. The mopeds and traffic gave me PTSD. Took a grab everywhere I went rather than navigating the buses.

Thanks all for your input. I'm an adventurous soul that prefers few tourists and more locals to engage with.

Likewise. I'd rather meet locals when traveling and not staying in the tourist areas but local neighbourhoods. Couchsurfing to contact locals for meetups / air bnb's in small towns.

Hanoi is a large city, and it certainly is possible to do that there.

There are literally millions of people in Hanoi, most of them are not tourists. Perhaps I misunderstood your initial question. Old Quarter certainly has lots of tourists. But there are many other areas. That said, it is a large city, and I do not think you should expect it to be anything like it was 30 years ago- in Hanoi or anywhere else in Vietnam (or in the world , bluntly).

To address this particular part of your question; I would say, yes, definitely, you can go through most of Vietnam without having to book much far in advance. I mean, you might get to some particularly remote villages and struggle to find somewhere to stay if you have not organised ahead of your arrival, but most places you could just turn up and figure out accom etc, especially since you sound like you'll be skirting the major tourist destinations (eg Sa Pa, Hoi An). And most places you stay - be it hotels or homestays, which it sounds like you might lean to and will be the only option in smaller towns - will be able to organise your onward travel at very short notice once you're ready to move on. It's only really if you wanted to stay at specific hotels/homestays in a given location that I'd recommend booking. Well, that and, like I say, really small/remote places.
FWIW, I agree with most of what has been said about Hanoi; yes, touristy in parts but IMO still charming and, like any big city, multi-faceted. Many neighbourhoods to explore where you'd likely be the only foreigner.

Actually, that sounds like things have not changed much since I was there. Part of my trip included hiring a driver and 4x4, doing a big loop out to Sa Pa, after returning to Hanoi from Ha Long Bay. That included discovering accommodations anywhere we could. Found a 'luxury secure room' near Dien Bien Phu to stay one night. Previous occupants were Air Force pilots circa Vietnam War with their original art and signatures on the walls. Steel bars included with key and lock, no charge. Didn't see a single tourist until Sa Pa. My kind of trip.

went to vietnam 15 years ago and then again last november. Did hcmc hue and hanoi. Had previously been to Hoi An and Ha Long Bay and wasnt interested in returning. HCMC and Ha noi easy to navigate on foot to tourist sites. - We really enjoyed hue, the imperial tombs and citadel are really interesting. There are tours of private homes, called the garden houses of hue which was really great, as you were able to meet people and see their homes. It was a most enjoyable day. We did not think we spent enough time there as there is also american war tourism which we had see in our previous trip. Really enjoyed vietnam, food was good, lots to see and do. Very efficient air transport since many of the airports were previously military.

You can find that in most of Vietnam (that aren't tourist magnets). Just avoid the tourist magnets like the big cities, Hoi An, Sa Pa, etc. I went to a village near Can Tho in 2023, decided to not follow the floating market circus, and discovered incredible local charm.

Tip: Enter Vietnam using your Italian passport as it is visa free for short stays. If you use your US passport you will require an evisa.

If you can,
Fly to Hue (I used Vietjet for $85) and spend at least 2 days there.
Clean, laid back historic city with plenty to see, especially the imperial palace.
Take the train from Hue to Da Nang ($7) for some spectacular scenery with cliffs dropping to the sea and you perched on the train track above.
Sit on left side (Southbound) seats 16, 20, 24 etc.
For beautiful beaches and sea food, Da Nang.
I didn't care for Hoi An but I just saw the area along the river with endless market/tourist trap.
May have issues with ATMs. I used SRB Bank with my overseas card.
Google translate is the only way to communicate as other languages are limited. Airport SIM available for $10.
I really enjoyed visiting Hanoi/Hue/Da Nang. 8 days.

would you all recommend Da Nang in early October?
Been to Koh Samui the last few years and despite being rainy season it was quite OK. Reading different stories about Da Nang as it's obviously more exposed?

Regular rainy season in Ko Samui is not equivalent to the lethal tropical cyclones that hit The Philippines and Central Vietnam during typhoon season every Sept/October. One could always skip through the rain and dodge the deluge: friends of mine who live in Hoi An say last year was mild, and I seem to recall reports on FT attesting to the same. If you haven't already, read up more on these storms that have hit over the last several years (Typhoon Trami, Oct '24; Sonca, Oct '22; Noru, Sept '22; Dianmu, Sept '21), and decide accordingly.

Agree with this post. .. Hue has lots to see, the citadel, imperial tombs. garden houses, good food - as well as historical sites from the war like the reunification bridge, quang tri... we used cash in vietnam, food was inexpensive, and international atm ..hsbc was not a problem. da nang is a big city ..the ride from hue to da nang via hai van pass is also nice.