First about the car, yes, I am in the same boat. Not that I would want one as it makes no sense to take on such an ongoing commitment , insurance, maintenance etc., even if it was possible. Curiously, I saw one YouTube video (I forgot the channel name) where someone managed to buy a car as a visitor but even they said they were lucky and the dealership went out of their way to help make it happen. I think they were an Australian or New Zealend couple but I forgot the channel name.
I actually really enjoy cycling around town in the eclectic bike, it is a lot of fun, more fun than driving around, and I normally use the narrow residential streets which makes it even more enjoyable. Occasional car rentals just make more sense to me rather than trying to find an angle to keep a car permanently parked at the house.
Now for your "keep-the-bones theory" — I actually googled, AI-ed and fact checked it because I'd heard the same thing. Turns out the rules changed very recently (April 2025) and a lot of what you read online is still describing the old rules.
Here is the verbatim fact check result, I quote:
"What changed: Japan revised the Building Standards Act in April 2025 and shrank something called the "Type 4 exemption" (4号特例). Under the old rules, 2-storey wooden houses didn't need building confirmation for major renovations — which is exactly why people could do full skeleton renovations on rebuild-restricted (再建築不可) properties while keeping the frame. Since April 2025, a 2-storey wooden house needs building confirmation for any "large-scale repair" — defined as replacing more than half of any principal structural element (walls, columns, floors, beams, roof, stairs). And here's the catch: confirmation requires the property to comply with current law, including the road-access requirement — which a 再建築不可 plot by definition fails. So the application generally can't be approved, which makes big structural renos on 2-storey rebuild-restricted houses effectively impossible now, legally at least.
What still works: smaller works below that "half of a structural element" line need no confirmation — kitchens, bathrooms, wallpaper, flooring, partial repairs. And single-storey houses under 200m² kept their exemption, so a 1-storey 再建築不可 house can still be renovated substantially. Some plots can also be rescued through an exception approval process (Building Standards Act Art. 43), but that's case-by-case with the municipality."
So for your plan, the practical takeaway: if a cheap place is cheap because it's 再建築不可, assume you can neither rebuild NOR gut-renovate it if it's 2 storeys — and verify anything in this area with a local architect or the municipal building office BEFORE money moves, because rules vary by municipality and forums (including this one!) are not the final word. Honestly, given your budget, I'd be looking at properties without that restriction at all — the discount isn't worth the handcuffs anymore !!
Can I ask — how often are you planning to be over, and for how long at a time? I ask because it genuinely changes the answer: a house you visit twice a year wants to be as close to turn-key as possible (managing a renovation from Canada is a project in itself!), whereas if you'll be there for longer stretches like me at the moment, a project house becomes much more realistic.
Hopefully more people reading this in the future can chime in their advise.