These are pretty much your current only options. And I guess you do not realise that used cars import haven't been legal since 1975.
Before owning any of these I suggest you learn a few simple facts about them. One I've already told you above. Another is that you will need to learn and take driving exam in 1990's or 2000's mid-size truck such as the Hilux or Mitsubishi L200. If you cannot do that, forget it, you'll never be able to drive these things.
And then you'll need to learn how to operate these cars. Carburettored engine definitely doesn't go like a fuel injected one. You'll have to learn these difference between them. And that's barely the tip of the iceberg.
Even the Toyota engine cars will have trouble operating reliably. There are many reasons why you don't see these sort of car everyday. They were literally made to last only 130,000-140,000km before dying off. It's what planned obsolescence does to a car. If the engine doesn't let go, something else will. You can keep the car longer than that, but eventually you'll realise that you spend a lot more than twice what the car cost in the first place. You are in Thailand ffs. Not freaking Michigan.
I do not want to sound like an arse. But I have to tell you now. What you're thinking is a harebrained idea. Something that is certainly possible, but monumentally stupid. Especially how ill-informed you currently are.