Also in-universe and IRL let's remember that even a Bicycle is 'advanced' technology that requires rubbers, chains, gears, mechanism, and a workforce that is basically a frivolity to produce.
A motorcycle requires a power source, luckily we seem to be ontop of mountains of rechargeable energy cells or even Fusion Cells but even then you'll want the cell in a hospital, a bedroom, a office, then maybe to vehicles and guns. The Wasteland isn't green enough, nor productive enough, to produce ethanol via corn; oil of course is right out.
A car is more of the same but now there's more shit to look after on a bigger scale.
A APC, AFV, Tank, and likewise just expedite that even more.
Steam, wood-steam or coal, is right out, though coal is apparently mined in Montana, but probably for personal use; such as we see with the Medieval Chinese who mined coal and knew it could heat shit up easily.
The earliest known vehicle is a Ox-Drawn cart; but Bighorners lay down if you put a pack on them so you're stuck with Brahmin for that.
Rafts, Catamarans, Dugouts, Canoes, Galleys even are easier but there's no civilization of any worth or note on the oceans for the *demand*, most people would just take a old boat and row it or put a battery in it and it's still fine; though in the Far, Far Future of Fallout I can surmise that maybe slews of Thalassocracies might emerge in the PNW, Far East Asia, and the like if wood and metal suffice and you have the population for rowers.
We have no horses and the impact of that will be immense. No Chariots. No Cavalry. No Knights. No Lancers, Horse Archers, Cataphracts, Outriders, Pistoliers, Demigunners, whatever. Horses were also used for public transport, goods transport, fieldwork. Our civilization basically started because the Yamana grabbed the horse, bred stronger ones, and either sold themselves as charioteers or took over as charioteers and then cavalry emerged later. (You could have Donkey-Mule Chariots and War Carts but we don't see them either).
Trains are still in use, probably again pre-war battery powered tech; and the NCR has the ability to make new tracks and hopefully new cars. By this the NCR could reinforce their gains and build a strong network akin to Pre-Automobile Crazy America where every damn county and town had a railroad.
Aircraft of course raise the complexity of their inner workings and cost on a society double or tenfold. Everyone is using Zeppelins, Dirigibles, Blimps, and Vertibirds; the first three might be 'easier' to construct but still require hydrogen or helium or somesuch else gas to be extracted and Vertibirds are probably built to be as rugged and adapatable as can be, with the drawbacks of a low payload, low armor, lowish speed, but hey you can fly in a steel chassis with miniguns and rockets and the enemy mostly cannot.